diff --git a/README.md b/README.md
index adb75e26fd8e2179a0095a5f4c07c5707c4639ed..3b6ecc6f43f99dae073ee3e50d9b6a8acd474d99 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ colorFrom: red
 colorTo: yellow
 sdk: gradio
 sdk_version: 6.20.0
-python_version: '3.12'
+python_version: '3.11'
 app_file: app.py
 pinned: false
 ---
diff --git a/openpi_runtime/openpi/__init__.py b/openpi_runtime/openpi/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/openpi_runtime/openpi/conftest.py b/openpi_runtime/openpi/conftest.py
new file mode 100644
index 0000000000000000000000000000000000000000..5002b629de77953e03f24157f6ba4c88fc448468
--- /dev/null
+++ b/openpi_runtime/openpi/conftest.py
@@ -0,0 +1,17 @@
+import os
+
+import pynvml
+import pytest
+
+
+def set_jax_cpu_backend_if_no_gpu() -> None:
+    try:
+        pynvml.nvmlInit()
+        pynvml.nvmlShutdown()
+    except pynvml.NVMLError:
+        # No GPU found.
+        os.environ["JAX_PLATFORMS"] = "cpu"
+
+
+def pytest_configure(config: pytest.Config) -> None:
+    set_jax_cpu_backend_if_no_gpu()
diff --git a/openpi_runtime/openpi/models/__init__.py b/openpi_runtime/openpi/models/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/openpi_runtime/openpi/models/gemma.py b/openpi_runtime/openpi/models/gemma.py
new file mode 100644
index 0000000000000000000000000000000000000000..d1623d19d12517977d55e193361c5ced481efbc8
--- /dev/null
+++ b/openpi_runtime/openpi/models/gemma.py
@@ -0,0 +1,459 @@
+# Copyright 2024 Big Vision Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Gemma adaptation for Pi, taken from big_vision.
+
+We follow this einsum axis naming convention:
+  B: batch
+  T: query length
+  S: k/v length
+  N: num query heads
+  K: num k/v heads
+  G: num query heads per k/v head
+  H: head dim
+  D: d_model ("features")
+"""
+
+from collections.abc import Sequence
+import dataclasses
+from typing import Literal, TypeAlias
+
+import einops
+import flax.linen as nn
+import jax
+import jax.numpy as jnp
+
+import openpi.models.lora as lora
+import openpi.shared.array_typing as at
+import openpi.training.sharding as sharding
+
+PALIGEMMA_VOCAB_SIZE = 257_152
+
+
+@dataclasses.dataclass
+class Config:
+    width: int
+    depth: int
+    mlp_dim: int
+    num_heads: int
+    num_kv_heads: int
+    head_dim: int
+    lora_configs: dict[str, lora.LoRAConfig] = dataclasses.field(default_factory=dict)
+
+
+Variant = Literal["dummy", "gemma_300m", "gemma_300m_lora", "gemma_2b", "gemma_2b_lora"]
+
+
+def get_config(variant: Variant) -> Config:
+    """Returns config for specified gemma variant."""
+    if variant == "dummy":
+        return Config(
+            width=64,
+            depth=4,
+            mlp_dim=128,
+            num_heads=8,
+            num_kv_heads=1,
+            head_dim=16,
+        )
+    if variant == "gemma_300m":
+        # 311M params
+        return Config(
+            width=1024,
+            depth=18,
+            mlp_dim=4096,
+            num_heads=8,
+            num_kv_heads=1,
+            head_dim=256,
+        )
+    if variant == "gemma_2b":
+        return Config(
+            width=2048,
+            depth=18,
+            mlp_dim=16_384,
+            num_heads=8,
+            num_kv_heads=1,
+            head_dim=256,
+        )
+    if variant == "gemma_2b_lora":
+        return Config(
+            width=2048,
+            depth=18,
+            mlp_dim=16_384,
+            num_heads=8,
+            num_kv_heads=1,
+            head_dim=256,
+            lora_configs={"attn": lora.LoRAConfig(rank=16, alpha=16.0), "ffn": lora.LoRAConfig(rank=16, alpha=16.0)},
+        )
+    if variant == "gemma_300m_lora":
+        # 311M params
+        return Config(
+            width=1024,
+            depth=18,
+            mlp_dim=4096,
+            num_heads=8,
+            num_kv_heads=1,
+            head_dim=256,
+            lora_configs={"attn": lora.LoRAConfig(rank=32, alpha=32.0), "ffn": lora.LoRAConfig(rank=32, alpha=32.0)},
+        )
+    raise ValueError(f"Unknown variant: {variant}")
+
+
+@at.typecheck
+class RMSNorm(nn.Module):
+    @nn.compact
+    def __call__(self, x, cond):
+        dtype = x.dtype  # original dtype, could be half-precision
+        var = jnp.mean(jnp.square(x.astype(jnp.float32)), axis=-1, keepdims=True)  # compute variance in float32
+        normed_inputs = jnp.asarray(x * jnp.reciprocal(jnp.sqrt(var + 1e-06)))  # compute normalization in float32
+        if cond is None:
+            # regular RMSNorm
+            scale = self.param("scale", nn.initializers.zeros_init(), (x.shape[-1]))
+            normed_inputs = normed_inputs * (
+                1 + scale
+            )  # scale by learned parameter in float32 (matches Flax implementation)
+            return normed_inputs.astype(dtype), None  # return in original dtype
+
+        # adaptive RMSNorm
+        modulation = nn.Dense(x.shape[-1] * 3, kernel_init=nn.initializers.zeros, dtype=dtype)(cond)
+        scale, shift, gate = jnp.split(modulation[:, None, :], 3, axis=-1)
+        normed_inputs = normed_inputs * (1 + scale) + shift  # scale and shift in float32
+        return normed_inputs.astype(dtype), gate
+
+
+@at.typecheck
+class Embedder(nn.Module):
+    """Embedder module."""
+
+    vocab_size: int
+    embed_dim: int
+
+    def setup(self):
+        self.input_embedding_table = self.param(
+            "input_embedding",
+            nn.initializers.normal(),
+            (self.vocab_size, self.embed_dim),
+        )
+
+    def encode(self, x):
+        x = self.input_embedding_table[(x,)]
+        x *= jnp.sqrt(self.embed_dim).astype(x.dtype)
+        return x
+
+    def decode(self, x):
+        return jnp.dot(x, self.input_embedding_table.T)
+
+
+@at.typecheck
+class Attention(nn.Module):
+    """Attention module."""
+
+    configs: Sequence[Config]
+
+    @nn.compact
+    def __call__(self, xs, positions, attn_mask, kv_cache):
+        # all experts must share the same head dim, num heads, and num kv heads for self-attention to work
+        assert all(config.head_dim == self.configs[0].head_dim for config in self.configs)
+        assert all(config.num_heads == self.configs[0].num_heads for config in self.configs)
+        assert all(config.num_kv_heads == self.configs[0].num_kv_heads for config in self.configs)
+
+        dtype = next(x.dtype for x in xs if x is not None)  # original dtype, could be half-precision
+
+        qkvs = []
+        for i, (x, config) in enumerate(zip(xs, self.configs, strict=True)):
+            if x is None:
+                continue
+            if config.num_kv_heads == config.num_heads:
+                qkv_einsum = lora.Einsum(
+                    shape=(3, config.num_heads, config.width, config.head_dim),
+                    name=_name("qkv_einsum", i),
+                    init_fn=nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0, 1)),
+                    lora_config=config.lora_configs.get("attn"),
+                )
+                qkvs.append(qkv_einsum("BSD,3KDH->3BSKH", x))
+            else:
+                q_einsum = lora.Einsum(
+                    shape=(config.num_heads, config.width, config.head_dim),
+                    name=_name("q_einsum", i),
+                    init_fn=nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0,)),
+                    lora_config=config.lora_configs.get("attn"),
+                )
+                q = q_einsum("BTD,NDH->BTNH", x)
+                kv_einsum = lora.Einsum(
+                    shape=(2, config.num_kv_heads, config.width, config.head_dim),
+                    name=_name("kv_einsum", i),
+                    init_fn=nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0, 1)),
+                    lora_config=config.lora_configs.get("attn"),
+                )
+                k, v = kv_einsum("BSD,2KDH->2BSKH", x)
+                qkvs.append((q, k, v))
+
+        q, k, v = (jnp.concatenate(y, axis=1) for y in zip(*qkvs, strict=True))
+
+        q = _apply_rope(q, positions=positions)
+        q *= self.configs[0].head_dim ** -0.5
+
+        k = _apply_rope(k, positions=positions)
+
+        # should still be half-precision here (if input was half-precision)
+        assert q.dtype == k.dtype == v.dtype == dtype
+
+        if kv_cache is not None:
+            cache_k, cache_v = kv_cache
+            k = jnp.concatenate([cache_k, k], axis=1)
+            v = jnp.concatenate([cache_v, v], axis=1)
+
+        q = einops.rearrange(q, "B T (K G) H -> B T K G H", K=self.configs[0].num_kv_heads)
+        logits = jnp.einsum("BTKGH,BSKH->BKGTS", q, k, preferred_element_type=jnp.float32)
+
+        if attn_mask.shape != (q.shape[0], 1, q.shape[1], k.shape[1]):
+            raise ValueError(
+                f"Attention mask with shape {attn_mask.shape} but shapes for q and k are: {q.shape} and {k.shape}"
+            )
+
+        # big_neg = jnp.finfo(logits.dtype).min
+        big_neg = -2.3819763e38  # See gemma/modules.py
+        masked_logits = jnp.where(attn_mask[:, :, None, :, :], logits, big_neg)
+
+        probs = jax.nn.softmax(masked_logits, axis=-1).astype(dtype)
+
+        encoded = jnp.einsum("BKGTS,BSKH->BTKGH", probs, v)
+        encoded = einops.rearrange(encoded, "B T K G H -> B T (K G) H")
+
+        out = []
+        start = 0
+        for i, (x, config) in enumerate(zip(xs, self.configs, strict=True)):
+            if x is not None:
+                end = start + x.shape[1]
+                out_einsum = lora.Einsum(
+                    shape=(config.num_heads, config.head_dim, config.width),
+                    name=_name("attn_vec_einsum", i),
+                    init_fn=nn.initializers.lecun_normal(in_axis=(-3, -2), out_axis=-1),
+                    lora_config=config.lora_configs.get("attn"),
+                )
+                out.append(out_einsum("BTNH,NHD->BTD", encoded[:, start:end]))
+                start = end
+            else:
+                out.append(None)
+
+        return out, (k, v)
+
+
+@at.typecheck
+class FeedForward(nn.Module):
+    """Feed forward module."""
+
+    features: int
+    hidden_dim: int
+
+    @nn.compact
+    def __call__(self, x):
+        dtype = x.dtype  # original dtype, could be half-precision
+        w_gating = self.param(
+            "gating_einsum",
+            nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0,)),
+            (2, self.features, self.hidden_dim),
+        ).astype(dtype)
+        ff_gate = jnp.dot(x, w_gating[0])
+        gate_value = nn.gelu(ff_gate)
+
+        ff1 = jnp.dot(x, w_gating[1])
+        activations = gate_value * ff1
+
+        w_linear = self.param(
+            "linear",
+            nn.initializers.lecun_normal(in_axis=-2, out_axis=-1),
+            (self.hidden_dim, self.features),
+        ).astype(dtype)
+        outputs = jnp.dot(activations, w_linear)
+        assert outputs.dtype == dtype
+        return outputs
+
+
+@at.typecheck
+class Block(nn.Module):
+    """Transformer block."""
+
+    configs: tuple[Config, ...]
+
+    dropout: float = 0.0
+    dropout_bdims: tuple[int, ...] = ()
+
+    @nn.compact
+    def __call__(self, xs, kv_cache, positions, attn_mask, adarms_cond, deterministic=True):  # noqa: FBT002
+        xs = sharding.activation_sharding_constraint(xs)
+        drop = nn.Dropout(self.dropout, self.dropout_bdims) if self.dropout else lambda x, _: x
+
+        attn = Attention(configs=self.configs, name="attn")
+
+        pre_attn = []
+        gates = []
+        for i, x in enumerate(xs):
+            if x is not None:
+                x, gate = RMSNorm(name=_name("pre_attention_norm", i))(x, adarms_cond[i])  # noqa: PLW2901
+            pre_attn.append(x)
+            gates.append(gate if x is not None else None)
+
+        pre_attn = sharding.activation_sharding_constraint(pre_attn)
+        post_attn, kv_cache = attn(pre_attn, positions, attn_mask, kv_cache)
+        post_attn = jax.tree.map(lambda x: drop(x, deterministic), post_attn)
+        post_attn = sharding.activation_sharding_constraint(post_attn)
+        xs = [_gated_residual(x, y, gate) for x, y, gate in zip(xs, post_attn, gates, strict=True)]
+        xs = sharding.activation_sharding_constraint(xs)
+
+        out = []
+        gates = []
+        for i, (x, config) in enumerate(zip(xs, self.configs, strict=True)):
+            if x is not None:
+                x, gate = RMSNorm(name=_name("pre_ffw_norm", i))(x, adarms_cond[i])  # noqa: PLW2901
+                x = lora.FeedForward(  # noqa: PLW2901
+                    features=config.width,
+                    hidden_dim=config.mlp_dim,
+                    name=_name("mlp", i),
+                    lora_config=config.lora_configs.get("ffn"),
+                )(x)
+            out.append(x)
+            gates.append(gate if x is not None else None)
+
+        out = sharding.activation_sharding_constraint(out)
+        out = jax.tree.map(lambda x: drop(x, deterministic), out)
+        xs = [_gated_residual(x, y, gate) for x, y, gate in zip(xs, out, gates, strict=True)]
+        xs = sharding.activation_sharding_constraint(xs)
+
+        return xs, kv_cache
+
+
+KVCache: TypeAlias = tuple[at.Float[at.Array, "l b _t _k _h"], at.Float[at.Array, "l b _t _v _h"]]
+
+
+@at.typecheck
+class Module(nn.Module):
+    """Transformer model, supporting a mixture of different weights for different tokens."""
+
+    configs: Sequence[Config]  # list of configs, one for each expert
+    embed_dtype: str
+
+    dropout: float = 0.0
+    dropout_bdims: tuple[int, ...] = ()  # Every float is dropped independently.
+    adarms: bool = False
+
+    def setup(self):
+        # all experts must have the same depth
+        assert all(config.depth == self.configs[0].depth for config in self.configs)
+
+        self.embedder = Embedder(
+            vocab_size=PALIGEMMA_VOCAB_SIZE,
+            embed_dim=self.configs[0].width,  # embedder for first expert only
+            name="embedder",
+        )
+        block_cls = nn.remat(
+            Block,
+            prevent_cse=False,
+            static_argnums=(5,),  # 0=self, 6=deterministic
+            policy=jax.checkpoint_policies.nothing_saveable,
+        )
+        self.layers = nn.scan(
+            block_cls,
+            variable_axes={"params": 0},
+            split_rngs={"params": True, "dropout": True},
+            in_axes=(
+                0,
+                nn.broadcast,
+                nn.broadcast,
+                nn.broadcast,
+                nn.broadcast,
+            ),  # 0=kv_cache, 1=positions, 2=mask, 3=adarms_cond, 4=deterministic
+            length=self.configs[0].depth,
+        )(
+            configs=self.configs,
+            dropout=self.dropout,
+            dropout_bdims=self.dropout_bdims,
+        )
+        self.final_norms = [RMSNorm(name=_name("final_norm", i)) for i in range(len(self.configs))]
+
+    @at.typecheck
+    def embed(self, tokens: at.Int[at.Array, "b t"]) -> at.Float[at.Array, "b t d"]:
+        return self.embedder.encode(tokens).astype(self.embed_dtype)
+
+    @at.typecheck
+    def __call__(
+        self,
+        # list of token arrays, one for each expert, or None if that expert should not be run
+        embedded: Sequence[at.Float[at.Array, "b _t _d"] | None],
+        positions: at.Int[at.Array, "b t"],
+        mask: at.Bool[at.Array, "b t s"],
+        adarms_cond: Sequence[at.Float[at.Array, "b _d"] | None] | None = None,
+        *,
+        kv_cache: KVCache | None = None,
+        deterministic: bool = True,
+    ) -> tuple[Sequence[at.Float[at.Array, "b _t _d"] | None], KVCache]:
+        embedded = jax.tree.map(lambda e: e.astype(self.embed_dtype), embedded)
+        mask = jnp.asarray(mask)[:, None, :, :]
+        if adarms_cond is None:
+            adarms_cond = [None] * len(self.configs)
+
+        embedded, kv_cache = self.layers(embedded, kv_cache, positions, mask, adarms_cond, deterministic)
+
+        assert all(e.dtype == jnp.dtype(self.embed_dtype) for e in embedded if e is not None)
+
+        return [
+            f(e, a)[0] if e is not None else e for f, e, a in zip(self.final_norms, embedded, adarms_cond, strict=True)
+        ], kv_cache
+
+    def init(self, use_adarms: Sequence[bool]):
+        """Convenience method for initializing all parameters, necessary due to the quirks of linen."""
+        self.embed(jnp.zeros((1, 1), dtype=jnp.int32))
+        self(
+            [jnp.zeros((1, 1, c.width)) for c in self.configs],
+            jnp.zeros((1, len(self.configs)), dtype=jnp.int32),
+            jnp.zeros((1, len(self.configs), len(self.configs)), dtype=bool),
+            adarms_cond=[jnp.zeros((1, c.width)) if u else None for u, c in zip(use_adarms, self.configs, strict=True)],
+        )
+
+
+def _apply_rope(x, *, positions, max_wavelength=10_000):
+    """Applies RoPE positions [B, L] to x [B, L, H, D]."""
+    freq_exponents = (2.0 / x.shape[-1]) * jnp.arange(x.shape[-1] // 2, dtype=jnp.float32)
+    timescale = max_wavelength**freq_exponents
+    radians = positions[..., None] / timescale[None, None, :]
+    radians = radians[..., None, :]
+    assert radians.dtype == jnp.float32
+    # radians.shape = [...,L,1,d=D/2]
+    sin, cos = jnp.sin(radians), jnp.cos(radians)
+    x1, x2 = jnp.split(x, 2, axis=-1)
+    res = jnp.concatenate([x1 * cos - x2 * sin, x2 * cos + x1 * sin], axis=-1)
+    assert res.dtype == jnp.float32
+    # The original bigvision impl allows RoPE to upcast to float32. It is then immediately downcast again to the cache
+    # dtype when in inference mode (but not in training mode). I don't think any of this was intentional. Based on the
+    # original DeepMind impl, as well as the widely-used transformers impl, it is ok to always downcast back to bfloat16
+    # here.
+    return res.astype(x.dtype)
+
+
+def _name(name, i):
+    # we name layers like this because we want the first expert's weights to have no suffix (e.g., "attn"), so that they
+    # can be loaded seamlessly from the existing PaliGemma checkpoint. subsequent experts will have a suffix (e.g.,
+    # "attn_1") and their weights will be initialized from scratch. in practice, we only use two experts -- PaliGemma,
+    # and the action expert.
+    if i == 0:
+        return name
+    return f"{name}_{i}"
+
+
+def _gated_residual(x, y, gate):
+    assert (x is None) == (y is None)
+    if x is None:
+        return None
+    if gate is None:
+        return x + y
+    return x + y * gate
diff --git a/openpi_runtime/openpi/models/gemma_fast.py b/openpi_runtime/openpi/models/gemma_fast.py
new file mode 100644
index 0000000000000000000000000000000000000000..eee39b4317dd3f42aa4d73e11dceee37e394c39d
--- /dev/null
+++ b/openpi_runtime/openpi/models/gemma_fast.py
@@ -0,0 +1,437 @@
+# Copyright 2024 Big Vision Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Gemma model implementation from big_vision/models/ppp/gemma.py (with small modifications for NNX compatibility)
+Used for FAST autoregressive policies.
+"""
+
+import dataclasses
+from typing import Literal, TypeAlias
+
+import einops
+import flax.linen as nn
+import jax
+import jax.numpy as jnp
+import ml_collections
+
+import openpi.models.lora as lora
+import openpi.shared.array_typing as at
+
+Variant = Literal["gemma_2b", "gemma_2b_lora"]
+
+
+def get_config(variant):
+    """Returns config for specified gemma variant."""
+    if variant == "gemma_2b":
+        return ml_collections.ConfigDict(
+            {
+                "variant": variant,
+                "width": 2048,
+                "depth": 18,
+                "mlp_dim": 16_384,
+                "num_heads": 8,
+                "num_kv_heads": 1,
+                "head_dim": 256,
+                "norm_eps": 1e-6,
+                "vocab_size": 257_152,
+                "scan": True,
+                "remat_policy": "nothing_saveable",
+            }
+        )
+    if variant == "gemma_2b_lora":
+        return ml_collections.ConfigDict(
+            {
+                "variant": variant,
+                "width": 2048,
+                "depth": 18,
+                "mlp_dim": 16_384,
+                "num_heads": 8,
+                "num_kv_heads": 1,
+                "head_dim": 256,
+                "norm_eps": 1e-6,
+                "vocab_size": 257_152,
+                "scan": True,
+                "remat_policy": "nothing_saveable",
+                "lora_configs": {
+                    "attn": lora.LoRAConfig(rank=16, alpha=16.0),
+                    "ffn": lora.LoRAConfig(rank=16, alpha=16.0),
+                },
+            }
+        )
+    raise ValueError(f"Unknown variant: {variant}")
+
+
+@at.typecheck
+class Einsum(nn.Module):
+    shape: tuple[int, ...]
+
+    @nn.compact
+    def __call__(self, eqn, x):
+        dtype = x.dtype  # original dtype, could be half-precision
+        w = self.param("w", nn.initializers.zeros_init(), self.shape).astype(dtype)
+        return jnp.einsum(eqn, x, w)
+
+
+@at.typecheck
+class RMSNorm(nn.Module):
+    @nn.compact
+    def __call__(self, x):
+        dtype = x.dtype  # original dtype, could be half-precision
+        scale = self.param("scale", nn.initializers.zeros_init(), (x.shape[-1]))
+        var = jnp.mean(jnp.square(x.astype(jnp.float32)), axis=-1, keepdims=True)  # compute variance in float32
+        normed_inputs = jnp.asarray(x * jnp.reciprocal(jnp.sqrt(var + 1e-06)))  # compute normalization in float32
+        normed_inputs = normed_inputs * (
+            1 + scale
+        )  # scale by learned parameter in float32 (matches Flax implementation)
+        return normed_inputs.astype(dtype)  # return in original dtype
+
+
+@at.typecheck
+class Embedder(nn.Module):
+    """Embedder module."""
+
+    vocab_size: int
+    embed_dim: int
+
+    def setup(self):
+        self.input_embedding_table = self.param(
+            "input_embedding",
+            nn.initializers.zeros_init(),
+            (self.vocab_size, self.embed_dim),
+        )
+
+    def encode(self, x):
+        x = self.input_embedding_table[(x,)]
+        x *= jnp.sqrt(self.embed_dim).astype(x.dtype)
+        return x
+
+    def decode(self, x):
+        return jnp.dot(x, self.input_embedding_table.T)
+
+
+@at.typecheck
+class Attention(nn.Module):
+    """Attention module."""
+
+    num_heads: int
+    num_kv_heads: int
+    features: int
+    head_dim: int
+
+    cache_dtype: str | None = None
+
+    lora_config: lora.LoRAConfig | None = None
+
+    def setup(self):
+        if self.num_kv_heads == self.num_heads:
+            self.qkv_einsum = lora.Einsum(
+                shape=(3, self.num_heads, self.features, self.head_dim),
+                name="qkv_einsum",
+                init_fn=nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0, 1)),
+                lora_config=self.lora_config,
+            )
+        else:
+            self.q_einsum = lora.Einsum(
+                shape=(self.num_heads, self.features, self.head_dim),
+                name="q_einsum",
+                init_fn=nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0,)),
+                lora_config=self.lora_config,
+            )
+            self.kv_einsum = lora.Einsum(
+                shape=(2, self.num_kv_heads, self.features, self.head_dim),
+                name="kv_einsum",
+                init_fn=nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0, 1)),
+                lora_config=self.lora_config,
+            )
+        self.attn_vec_einsum = lora.Einsum(
+            shape=(self.num_heads, self.head_dim, self.features),
+            name="attn_vec_einsum",
+            init_fn=nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0,)),
+            lora_config=self.lora_config,
+        )
+
+    def _init_cache(self, k, v, cache_size):
+        """Initialize KV cache"""
+        prefill_len = k.shape[1]
+        pad_width = ((0, 0), (0, cache_size - prefill_len), (0, 0), (0, 0))
+        cache_dtype = self.cache_dtype or k.dtype
+        k_cache = jnp.pad(k.astype(cache_dtype), pad_width)
+        v_cache = jnp.pad(v.astype(cache_dtype), pad_width)
+        idx = jnp.zeros((k.shape[0],), dtype=jnp.int32) + prefill_len
+        return idx, k_cache, v_cache
+
+    def _update_cache(self, k, v, idx, k_cache, v_cache):
+        """Update KV cache with new values"""
+        assert k.shape[1] == 1, "Only support kv-cache updates of length 1"
+        indices = (0, idx[0], 0, 0)
+        cache_dtype = self.cache_dtype or k.dtype
+        k_new = jax.lax.dynamic_update_slice(k_cache, k.astype(cache_dtype), indices)
+        v_new = jax.lax.dynamic_update_slice(v_cache, v.astype(cache_dtype), indices)
+        idx_new = idx + 1
+        return idx_new, k_new, v_new
+
+    @nn.compact
+    def __call__(self, x, positions, attn_mask, kv_cache, decode, deterministic=True):  # noqa: FBT002
+        dtype = x.dtype  # original dtype, could be half-precision
+        if self.num_kv_heads == self.num_heads:
+            q, k, v = self.qkv_einsum("BSD,3KDH->3BSKH", x)
+        else:
+            q = self.q_einsum("BTD,NDH->BTNH", x)
+            k, v = self.kv_einsum("BSD,2KDH->2BSKH", x)
+
+        q = _apply_rope(q, positions=positions)  # promotes to float32
+        q *= self.head_dim**-0.5
+
+        k = _apply_rope(k, positions=positions)  # promotes to float32
+
+        if kv_cache is None:
+            idx, k_cache, v_cache = self._init_cache(k, v, attn_mask.shape[-1])
+        else:
+            idx, k_cache, v_cache = kv_cache
+            idx, k_cache, v_cache = self._update_cache(k, v, idx, k_cache, v_cache)
+
+        k, v = k_cache, v_cache
+        kv_cache = (idx, k_cache, v_cache)
+
+        q = einops.rearrange(q, "B T (K G) H -> B T K G H", K=self.num_kv_heads)
+        logits = jnp.einsum("BTKGH,BSKH->BKGTS", q, k, preferred_element_type=jnp.float32)
+
+        if attn_mask.shape != (q.shape[0], 1, q.shape[1], k.shape[1]):
+            raise ValueError(
+                f"Attention mask with shape {attn_mask.shape} but shapes for q and k are: {q.shape} and {k.shape}"
+            )
+
+        # big_neg = jnp.finfo(logits.dtype).min
+        big_neg = -2.3819763e38  # See gemma/modules.py
+        masked_logits = jnp.where(attn_mask[:, :, None, :, :], logits, big_neg)
+
+        probs = jax.nn.softmax(masked_logits, axis=-1).astype(dtype)
+
+        encoded = jnp.einsum("BKGTS,BSKH->BTKGH", probs, v)
+        encoded = einops.rearrange(encoded, "B T K G H -> B T (K G) H")
+        return self.attn_vec_einsum("BTNH,NHD->BTD", encoded), kv_cache
+
+
+@at.typecheck
+class Block(nn.Module):
+    """Transformer block."""
+
+    num_heads: int
+    num_kv_heads: int
+    embed_dim: int
+    head_dim: int
+    hidden_dim: int
+
+    dropout: float = 0.0
+    dropout_bdims: tuple[int, ...] = ()
+    cache_dtype: str | None = None
+    lora_configs: ml_collections.ConfigDict = dataclasses.field(default_factory=ml_collections.ConfigDict)
+
+    def setup(self):
+        self.pre_attention_norm = RMSNorm()
+        self.attn = Attention(
+            num_heads=self.num_heads,
+            num_kv_heads=self.num_kv_heads,
+            features=self.embed_dim,
+            head_dim=self.head_dim,
+            cache_dtype=self.cache_dtype,
+            lora_config=self.lora_configs.get("attn"),
+        )
+        self.pre_ffw_norm = RMSNorm()
+        self.mlp = lora.FeedForward(
+            features=self.embed_dim, hidden_dim=self.hidden_dim, name="mlp", lora_config=self.lora_configs.get("ffn")
+        )
+        if self.dropout:
+            self.drop = nn.Dropout(self.dropout, self.dropout_bdims)
+        else:
+            self.drop = lambda x, _: x
+
+    def __call__(self, x, kv_cache, positions, attn_mask, decode, deterministic=True):  # noqa: FBT002
+        x = nn.with_logical_constraint(x, ("act_batch", "act_len", "act_emb"))
+        inputs_normalized = self.pre_attention_norm(x)
+        attn_output, kv_cache = self.attn(inputs_normalized, positions, attn_mask, kv_cache, decode, deterministic)
+        attn_output = self.drop(attn_output, deterministic)
+        attn_output += x
+        residual = attn_output
+        attn_output = self.pre_ffw_norm(attn_output)
+        outputs = self.mlp(attn_output)
+        outputs = self.drop(outputs, deterministic)
+        outputs = residual + outputs
+        return outputs, kv_cache
+
+
+KVCache: TypeAlias = tuple[at.Int[at.Array, " b"], at.Float[at.Array, "b _t _k _h"], at.Float[at.Array, "b _t _v _h"]]
+
+
+@at.typecheck
+class Module(nn.Module):
+    """gemma model."""
+
+    variant: str
+
+    width: int
+    depth: int
+    mlp_dim: int
+    num_heads: int
+    num_kv_heads: int
+    head_dim: int
+    norm_eps: float
+    vocab_size: int
+    embed_dtype: str
+
+    dropout: float = 0.0
+    dropout_bdims: tuple[int, ...] = ()  # Every float is dropped independently.
+    cache_dtype: str | None = None
+
+    scan: bool = False
+    remat_policy: str = "none"
+    lora_configs: ml_collections.ConfigDict = dataclasses.field(default_factory=ml_collections.ConfigDict)
+
+    @nn.compact
+    def __call__(
+        self,
+        tokens=None,
+        embedded_prefix=None,
+        embed_only=False,  # noqa: FBT002
+        pre_logits=None,
+        positions=None,
+        mask=None,
+        decode=False,  # noqa: FBT002
+        kv_cache=None,
+        deterministic=True,  # noqa: FBT002
+        return_prelogits=False,  # noqa: FBT002
+    ):
+        """Embed only, or complete forward pass.
+
+        Args:
+          tokens: Embedded, then and appended to `embedded_prefix`. Can be None.
+          embedded_prefix: Optional prefix that is already embedded.
+          embed_only: Whether to compute embeddings only.
+          pre_logits: If present computes logits from pre_logits and returns.
+          positions: Optional `[B, T]` allows to specify the absolute position of
+            the tokens.
+          mask: Optional attention mask `[B, T, S]`.
+          decode: Whether to use kv-cache. Caller must pass masks and positions.
+          deterministic: Forwarded to all dropout layers.
+          return_prelogits: Whether to return the pre-logits.
+
+        Returns:
+          If `embed_only=False`, then `(logits, out)` will be returned.
+          If `embed_only=True`, then the embeddings will be returned.
+          If `return_prelogits=True`, then the pre-logits will be returned.
+        """
+        out = {}
+
+        embedder = Embedder(vocab_size=self.vocab_size, embed_dim=self.width, name="embedder")
+
+        if pre_logits is not None:
+            x = out["pre_logits"] = pre_logits
+            logits = out["logits"] = embedder.decode(x)
+            return logits, out
+
+        x = []
+        if embedded_prefix is not None:
+            x.append(embedded_prefix)
+        if tokens is not None:
+            x.append(embedder.encode(tokens))
+
+        x = jnp.concatenate(x, axis=-2)
+        x = x.astype(self.embed_dtype)
+        batch_size, seq_len, width = x.shape
+
+        if embed_only:
+            return x
+
+        if decode:
+            assert positions is not None and mask is not None, (  # noqa: PT018
+                "Must explicitly pass positions and mask for decoding."
+            )
+
+        if positions is None:
+            positions = jnp.arange(seq_len).astype(jnp.int32)[None, :]
+        assert positions.shape[1] == x.shape[1], (positions.shape, x.shape)
+
+        if mask is None:
+            mask = nn.attention.make_causal_mask(jnp.ones([batch_size, seq_len]))
+        if mask.ndim == 3:
+            mask = mask[:, None, :, :]
+        cache_size = max(seq_len, mask.shape[-1])
+        assert mask.shape == (batch_size, 1, seq_len, cache_size), mask.shape
+
+        if self.remat_policy == "none":
+            block_cls = Block
+        else:
+            block_cls = nn.remat(
+                Block,
+                prevent_cse=not self.scan,
+                static_argnums=(5, 6),  # 0=self, 5=decode, 6=deterministic
+                policy=getattr(jax.checkpoint_policies, self.remat_policy),
+            )
+
+        block_kw = {
+            "num_heads": self.num_heads,
+            "head_dim": self.head_dim,
+            "num_kv_heads": self.num_kv_heads,
+            "embed_dim": width,
+            "hidden_dim": self.mlp_dim,
+            "dropout": self.dropout,
+            "dropout_bdims": self.dropout_bdims,
+            "cache_dtype": self.cache_dtype,
+            "lora_configs": self.lora_configs,
+        }
+        layers = self.scope.push("layers")
+        blocks = [
+            nn.scan(
+                block_cls,
+                variable_axes={"params": 0},
+                split_rngs={"params": True, "dropout": True},
+                in_axes=(0, nn.broadcast, nn.broadcast, nn.broadcast, nn.broadcast),  # 0=kv_cache, 1=positions, 2=mask
+                length=self.depth,
+            )(parent=layers, **block_kw)
+        ]
+        for block in blocks:
+            x, kv_cache = block(x, kv_cache, positions, mask, decode, deterministic)
+
+        assert x.dtype == jnp.dtype(self.embed_dtype)  # Sanity check.
+        out["encoded"] = x
+
+        x = RMSNorm(name="final_norm")(x)
+        out["pre_logits"] = x
+        if return_prelogits:
+            return x, kv_cache, out
+
+        x = embedder.decode(x)
+        out["logits"] = x
+
+        return x, kv_cache, out
+
+    def init(self):
+        """Convenience method for initializing all parameters, necessary due to the quirks of linen."""
+        self(jnp.zeros((1, 1), dtype=jnp.int32))
+
+
+def _apply_rope(x, *, positions, max_wavelength=10_000):
+    """Applies RoPE positions [B, L] to x [B, L, H, D]."""
+    freq_exponents = (2.0 / x.shape[-1]) * jnp.arange(x.shape[-1] // 2, dtype=jnp.float32)
+    timescale = max_wavelength**freq_exponents
+    radians = positions[..., None] / timescale[None, None, :]
+    radians = radians[..., None, :]
+    assert radians.dtype == jnp.float32
+    # radians.shape = [...,L,1,d=D/2]
+    sin, cos = jnp.sin(radians), jnp.cos(radians)
+    x1, x2 = jnp.split(x, 2, axis=-1)
+    res = jnp.concatenate([x1 * cos - x2 * sin, x2 * cos + x1 * sin], axis=-1)
+    assert res.dtype == jnp.float32
+    return res
diff --git a/openpi_runtime/openpi/models/lora.py b/openpi_runtime/openpi/models/lora.py
new file mode 100644
index 0000000000000000000000000000000000000000..3dfff5b4f22ff42f73298037a77df900c6b11d75
--- /dev/null
+++ b/openpi_runtime/openpi/models/lora.py
@@ -0,0 +1,148 @@
+import math
+import re
+
+import flax.linen as nn
+import flax.struct as struct
+import jax.numpy as jnp
+
+import openpi.shared.array_typing as at
+
+
+@struct.dataclass
+class LoRAConfig:
+    """Configuration for LoRA."""
+
+    # LoRA rank.
+    rank: int
+    # LoRA scaling factor.
+    alpha: float = 1.0
+    # Initialization function for LoRA parameters.
+    init_fn: nn.initializers.Initializer = nn.initializers.normal(stddev=0.01)
+    # Enable rank-stabilized LoRA: https://arxiv.org/pdf/2312.03732
+    rslora: bool = False
+    # Axes in the weight to apply LoRA to. Should typically be the last two axes.
+    axes: tuple[int, int] = (-2, -1)
+    # Axis label which is used by LoRA in einsum equations. Must not be present in the original equation.
+    label: str = "L"
+
+    @property
+    def scaling_value(self) -> float:
+        return self.alpha / math.sqrt(self.rank) if self.rslora else self.alpha / self.rank
+
+
+class Einsum(nn.Module):
+    """Einsum with LoRA support. Can be used as a drop-in replacement for the Gemma Einsum."""
+
+    # Shape of the weight.
+    shape: tuple[int, ...]
+    # Initialization function for the weight.
+    init_fn: nn.initializers.Initializer = nn.initializers.zeros
+    # If not None, apply LoRA to the weight.
+    lora_config: LoRAConfig | None = None
+
+    def setup(self):
+        self.w = self.param("w", self.init_fn, self.shape)
+
+        if config := self.lora_config:
+            # Setup LoRA parameters.
+            shape_a, shape_b = list(self.shape), list(self.shape)
+            shape_a[config.axes[1]] = config.rank
+            shape_b[config.axes[0]] = config.rank
+            self.w_a = self.param("lora_a", config.init_fn, shape_a)
+            self.w_b = self.param("lora_b", config.init_fn, shape_b)
+
+    @nn.compact
+    def __call__(self, eqn: str, x):
+        dtype = x.dtype  # original dtype, could be half-precision
+        result = jnp.einsum(eqn, x, self.w.astype(dtype))
+
+        if config := self.lora_config:
+            eqn_a, eqn_b = self._make_lora_eqns(eqn)
+            lora = jnp.einsum(eqn_a, x, self.w_a.astype(dtype))
+            lora = jnp.einsum(eqn_b, lora, self.w_b.astype(dtype))
+            result = result + lora * config.scaling_value
+
+        return result
+
+    def _make_lora_eqns(self, eqn: str) -> tuple[str, str]:
+        if "L" in eqn:
+            raise ValueError(f"L already in eqn: {eqn}")
+        if not (m := re.match("(.*),(.*)->(.*)", eqn)):
+            raise ValueError(f"Unsupported einsum eqn: {eqn}")
+        lhs, rhs, out = m.groups()
+
+        assert self.lora_config is not None
+        a_label, b_label = (rhs[x] for x in self.lora_config.axes)
+        label = self.lora_config.label
+
+        a_rhs = rhs.replace(b_label, label)
+        a_out = out.replace(b_label, label)
+        eqn_a = f"{lhs},{a_rhs}->{a_out}"
+
+        b_rhs = rhs.replace(a_label, label)
+        eqn_b = f"{a_out},{b_rhs}->{out}"
+
+        return eqn_a, eqn_b
+
+
+class FeedForward(nn.Module):
+    """Feed forward module."""
+
+    features: int
+    hidden_dim: int
+    # If not None, apply LoRA to the weight.
+    lora_config: LoRAConfig | None = None
+
+    def setup(self):
+        self.w_gating = self.param(
+            "gating_einsum",
+            nn.initializers.lecun_normal(in_axis=-2, out_axis=-1, batch_axis=(0,)),
+            (2, self.features, self.hidden_dim),
+        )
+        self.w_linear = self.param(
+            "linear",
+            nn.initializers.lecun_normal(in_axis=-2, out_axis=-1),
+            (self.hidden_dim, self.features),
+        )
+        self.w_gating_lora = None
+        self.w_linear_lora = None
+        if self.lora_config:
+            # Setup LoRA parameters.
+            # TODO: follow up with a simplified init_fn api.
+            self.w_gating_lora = (
+                self.param("gating_einsum_lora_a", self.lora_config.init_fn, (2, self.features, self.lora_config.rank)),
+                self.param(
+                    "gating_einsum_lora_b", self.lora_config.init_fn, (2, self.lora_config.rank, self.hidden_dim)
+                ),
+            )
+            self.w_linear_lora = (
+                self.param("linear_lora_a", self.lora_config.init_fn, (self.hidden_dim, self.lora_config.rank)),
+                self.param("linear_lora_b", self.lora_config.init_fn, (self.lora_config.rank, self.features)),
+            )
+
+    @nn.compact
+    def __call__(self, x):
+        dtype = x.dtype  # original dtype, could be half-precision
+        ff_gate = self._dot(
+            x,
+            self.w_gating[0],
+            None if self.w_gating_lora is None else (self.w_gating_lora[0][0], self.w_gating_lora[1][0]),
+        )
+        gate_value = nn.gelu(ff_gate)
+
+        ff1 = self._dot(
+            x,
+            self.w_gating[1],
+            None if self.w_gating_lora is None else (self.w_gating_lora[0][1], self.w_gating_lora[1][1]),
+        )
+        activations = gate_value * ff1
+
+        outputs = self._dot(activations, self.w_linear, self.w_linear_lora)
+        assert outputs.dtype == dtype
+        return outputs
+
+    def _dot(self, x: at.Array, w: at.Array, lora_weights: tuple[at.Array, at.Array] | None) -> at.Array:
+        base = jnp.dot(x, w.astype(x.dtype))
+        if lora_weights is None:
+            return base
+        return base + jnp.dot(jnp.dot(x, lora_weights[0].astype(x.dtype)), lora_weights[1].astype(x.dtype))
diff --git a/openpi_runtime/openpi/models/model.py b/openpi_runtime/openpi/models/model.py
new file mode 100644
index 0000000000000000000000000000000000000000..29618b49453742266fe6e4a5815ceee06d815f3b
--- /dev/null
+++ b/openpi_runtime/openpi/models/model.py
@@ -0,0 +1,332 @@
+import abc
+from collections.abc import Sequence
+import dataclasses
+import enum
+import logging
+import pathlib
+from typing import Generic, TypeVar
+
+import augmax
+from flax import nnx
+from flax import struct
+from flax import traverse_util
+import jax
+import jax.numpy as jnp
+import numpy as np
+import orbax.checkpoint as ocp
+import safetensors
+import torch
+
+from openpi.models_pytorch import pi0_pytorch
+from openpi.shared import image_tools
+import openpi.shared.array_typing as at
+
+logger = logging.getLogger("openpi")
+
+# Type variable for array types (JAX arrays, PyTorch tensors, or numpy arrays)
+ArrayT = TypeVar("ArrayT", bound=jax.Array | torch.Tensor | np.ndarray)
+
+
+class ModelType(enum.Enum):
+    """Supported model types."""
+
+    PI0 = "pi0"
+    PI0_FAST = "pi0_fast"
+    PI05 = "pi05"
+
+
+# The model always expects these images
+IMAGE_KEYS = (
+    "base_0_rgb",
+    "left_wrist_0_rgb",
+    "right_wrist_0_rgb",
+)
+
+
+# This may need change if we release a small model.
+IMAGE_RESOLUTION = (224, 224)
+
+
+# Data format
+#
+# Data transforms produce the model input as a nested dictionary which is later converted
+# into `Obesrvation` and `Actions` objects. See below.
+#
+# In the dictory form, this data should look like:
+# {
+#     # Observation data.
+#     "image": {
+#         "base_0_rgb": (float32|uint8)[*b, h, w, 3],  # RGB image in [-1, 1] or [0, 255]
+#         ...  # Additional camera views
+#     },
+#     "image_mask": {
+#         "base_0_rgb": bool[*b],  # True if image is valid
+#         ...  # Masks for additional views
+#     },
+#     "state": float32[*b, s],  # Low-dimensional robot state
+#     "tokenized_prompt": int32[*b, l],  # Optional, tokenized language prompt
+#     "tokenized_prompt_mask": bool[*b, l],  # Optional, mask for tokenized prompt
+#     "token_ar_mask": int32[*b, l],  # Optional, autoregressive mask for FAST model
+#     "token_loss_mask": bool[*b, l],  # Optional, loss mask for FAST model
+#
+#      # Actions data.
+#      "actions": float32[*b ah ad]
+# }
+# where:
+#   *b = batch dimensions
+#   h,w = image height/width
+#   s = state dimension
+#   l = sequence length
+#
+@at.typecheck
+@struct.dataclass
+class Observation(Generic[ArrayT]):
+    """Holds observations, i.e., inputs to the model.
+
+    See `Observation.from_dict` to see the expected dictionary form. This is the format
+    that should be produced by the data transforms.
+    """
+
+    # Images, in [-1, 1] float32.
+    images: dict[str, at.Float[ArrayT, "*b h w c"]]
+    # Image masks, with same keys as images.
+    image_masks: dict[str, at.Bool[ArrayT, "*b"]]
+    # Low-dimensional robot state.
+    state: at.Float[ArrayT, "*b s"]
+
+    # Tokenized prompt.
+    tokenized_prompt: at.Int[ArrayT, "*b l"] | None = None
+    # Tokenized prompt mask.
+    tokenized_prompt_mask: at.Bool[ArrayT, "*b l"] | None = None
+
+    # pi0-fast model specific fields.
+
+    # Token auto-regressive mask (for FAST autoregressive model).
+    token_ar_mask: at.Int[ArrayT, "*b l"] | None = None
+    # Token loss mask (for FAST autoregressive model).
+    token_loss_mask: at.Bool[ArrayT, "*b l"] | None = None
+
+    @classmethod
+    def from_dict(cls, data: at.PyTree[ArrayT]) -> "Observation[ArrayT]":
+        """This method defines the mapping between unstructured data (i.e., nested dict) to the structured Observation format."""
+        # Ensure that tokenized_prompt and tokenized_prompt_mask are provided together.
+        if ("tokenized_prompt" in data) != ("tokenized_prompt_mask" in data):
+            raise ValueError("tokenized_prompt and tokenized_prompt_mask must be provided together.")
+        # If images are uint8, convert them to [-1, 1] float32.
+        for key in data["image"]:
+            if data["image"][key].dtype == np.uint8:
+                data["image"][key] = data["image"][key].astype(np.float32) / 255.0 * 2.0 - 1.0
+            elif hasattr(data["image"][key], "dtype") and data["image"][key].dtype == torch.uint8:
+                data["image"][key] = data["image"][key].to(torch.float32).permute(0, 3, 1, 2) / 255.0 * 2.0 - 1.0
+        return cls(
+            images=data["image"],
+            image_masks=data["image_mask"],
+            state=data["state"],
+            tokenized_prompt=data.get("tokenized_prompt"),
+            tokenized_prompt_mask=data.get("tokenized_prompt_mask"),
+            token_ar_mask=data.get("token_ar_mask"),
+            token_loss_mask=data.get("token_loss_mask"),
+        )
+
+    def to_dict(self) -> at.PyTree[ArrayT]:
+        """Convert the Observation to a nested dict."""
+        result = dataclasses.asdict(self)
+        result["image"] = result.pop("images")
+        result["image_mask"] = result.pop("image_masks")
+        return result
+
+
+# Defines the format of the actions. This field is included as "actions" inside the dictionary
+# produced by the data transforms.
+Actions = at.Float[ArrayT, "*b ah ad"]
+
+
+def preprocess_observation(
+    rng: at.KeyArrayLike | None,
+    observation: Observation,
+    *,
+    train: bool = False,
+    image_keys: Sequence[str] = IMAGE_KEYS,
+    image_resolution: tuple[int, int] = IMAGE_RESOLUTION,
+) -> Observation:
+    """Preprocess the observations by performing image augmentations (if train=True), resizing (if necessary), and
+    filling in a default image mask (if necessary).
+    """
+
+    if not set(image_keys).issubset(observation.images):
+        raise ValueError(f"images dict missing keys: expected {image_keys}, got {list(observation.images)}")
+
+    batch_shape = observation.state.shape[:-1]
+
+    out_images = {}
+    for key in image_keys:
+        image = observation.images[key]
+        if image.shape[1:3] != image_resolution:
+            logger.info(f"Resizing image {key} from {image.shape[1:3]} to {image_resolution}")
+            image = image_tools.resize_with_pad(image, *image_resolution)
+
+        if train:
+            # Convert from [-1, 1] to [0, 1] for augmax.
+            image = image / 2.0 + 0.5
+
+            transforms = []
+            if "wrist" not in key:
+                height, width = image.shape[1:3]
+                transforms += [
+                    augmax.RandomCrop(int(width * 0.95), int(height * 0.95)),
+                    augmax.Resize(width, height),
+                    augmax.Rotate((-5, 5)),
+                ]
+            transforms += [
+                augmax.ColorJitter(brightness=0.3, contrast=0.4, saturation=0.5),
+            ]
+            sub_rngs = jax.random.split(rng, image.shape[0])
+            image = jax.vmap(augmax.Chain(*transforms))(sub_rngs, image)
+
+            # Back to [-1, 1].
+            image = image * 2.0 - 1.0
+
+        out_images[key] = image
+
+    # obtain mask
+    out_masks = {}
+    for key in out_images:
+        if key not in observation.image_masks:
+            # do not mask by default
+            out_masks[key] = jnp.ones(batch_shape, dtype=jnp.bool)
+        else:
+            out_masks[key] = jnp.asarray(observation.image_masks[key])
+
+    return Observation(
+        images=out_images,
+        image_masks=out_masks,
+        state=observation.state,
+        tokenized_prompt=observation.tokenized_prompt,
+        tokenized_prompt_mask=observation.tokenized_prompt_mask,
+        token_ar_mask=observation.token_ar_mask,
+        token_loss_mask=observation.token_loss_mask,
+    )
+
+
+@dataclasses.dataclass(frozen=True)
+class BaseModelConfig(abc.ABC):
+    """Configuration shared by all models. Specific models should inherit from this class, and implement the `create`
+    method to create the corresponding model.
+    """
+
+    # Action space dimension.
+    action_dim: int
+    # Action sequence length.
+    action_horizon: int
+    # Tokenized prompt maximum length.
+    max_token_len: int
+
+    @property
+    @abc.abstractmethod
+    def model_type(self) -> ModelType:
+        """The model type."""
+
+    @abc.abstractmethod
+    def create(self, rng: at.KeyArrayLike) -> "BaseModel":
+        """Create a new model, initializing parameters."""
+
+    def load(self, params: at.Params, *, remove_extra_params: bool = True) -> "BaseModel":
+        """Create a model with the given parameters."""
+        model = nnx.eval_shape(self.create, jax.random.key(0))
+        graphdef, state = nnx.split(model)
+        if remove_extra_params:
+            params = ocp.transform_utils.intersect_trees(state.to_pure_dict(), params)
+        at.check_pytree_equality(expected=state.to_pure_dict(), got=params, check_shapes=True, check_dtypes=False)
+        state.replace_by_pure_dict(params)
+        return nnx.merge(graphdef, state)
+
+    def load_pytorch(self, train_config, weight_path: str):
+        logger.info(f"train_config: {train_config}")
+        model = pi0_pytorch.PI0Pytorch(config=train_config.model)
+        safetensors.torch.load_model(model, weight_path)
+        return model
+
+    @abc.abstractmethod
+    def inputs_spec(self, *, batch_size: int = 1) -> tuple[Observation, Actions]:
+        """Returns the input specification for the model. Values are jax.ShapeDtypeStruct."""
+
+    def fake_obs(self, batch_size: int = 1) -> Observation:
+        observation_spec, _ = self.inputs_spec(batch_size=batch_size)
+        return jax.tree.map(lambda x: jnp.ones(x.shape, x.dtype), observation_spec)
+
+    def fake_act(self, batch_size: int = 1) -> Actions:
+        _, action_spec = self.inputs_spec(batch_size=batch_size)
+        return jax.tree.map(lambda x: jnp.ones(x.shape, x.dtype), action_spec)
+
+
+@dataclasses.dataclass
+class BaseModel(nnx.Module, abc.ABC):
+    """Base class for all model implementations. Specific models should inherit from this class. They should call
+    super().__init__() to initialize the shared attributes (action_dim, action_horizon, and max_token_len).
+    """
+
+    action_dim: int
+    action_horizon: int
+    max_token_len: int
+
+    @abc.abstractmethod
+    def compute_loss(
+        self,
+        rng: at.KeyArrayLike,
+        observation: Observation,
+        actions: Actions,
+        *,
+        train: bool = False,
+    ) -> at.Float[at.Array, "*b ah"]: ...
+
+    @abc.abstractmethod
+    def sample_actions(self, rng: at.KeyArrayLike, observation: Observation, **kwargs) -> Actions: ...
+
+
+def restore_params(
+    params_path: pathlib.Path | str,
+    *,
+    restore_type: type[np.ndarray] | type[jax.Array] = jax.Array,
+    dtype: jnp.dtype | None = None,
+    sharding: jax.sharding.Sharding | None = None,
+) -> at.Params:
+    """Restores unstructured params PyTree from a checkpoint.
+
+    This works with checkpoints saved with `save_state` during openpi training (see `training/checkpoints.py`) as
+    well as pre-trained checkpoints released for openpi.
+
+    Args:
+        params_path: The local path to the checkpoint directory.
+        restore_type: The type to restore the params as. Can be set to `np.ndarray` to load the params as a numpy array.
+        dtype: The dtype to restore all params as. If not provided, will use the original dtype from the checkpoint.
+        sharding: The sharding to use for the params. If not provided, the params will be replicated across all devices.
+
+    Returns:
+        The restored params.
+    """
+    params_path = pathlib.Path(params_path).resolve() if not str(params_path).startswith("gs://") else params_path
+
+    if restore_type is jax.Array and sharding is None:
+        mesh = jax.sharding.Mesh(jax.devices(), ("x",))
+        sharding = jax.sharding.NamedSharding(mesh, jax.sharding.PartitionSpec())
+
+    with ocp.PyTreeCheckpointer() as ckptr:
+        metadata = ckptr.metadata(params_path)
+        item = {"params": metadata["params"]}
+
+        params = ckptr.restore(
+            params_path,
+            ocp.args.PyTreeRestore(
+                item=item,
+                restore_args=jax.tree.map(
+                    lambda _: ocp.ArrayRestoreArgs(sharding=sharding, restore_type=restore_type, dtype=dtype), item
+                ),
+            ),
+        )["params"]
+
+    # If the params were saved with `save_state` during openpi training, every key path will end with "value", which is
+    # added by `nnx.State`. We remove the "value" suffix here and always return what NNX calls a "pure dict".
+    flat_params = traverse_util.flatten_dict(params)
+    if all(kp[-1] == "value" for kp in flat_params):
+        flat_params = {kp[:-1]: v for kp, v in flat_params.items()}
+    return traverse_util.unflatten_dict(flat_params)
diff --git a/openpi_runtime/openpi/models/pi0.py b/openpi_runtime/openpi/models/pi0.py
new file mode 100644
index 0000000000000000000000000000000000000000..ae7c4590f330f160aa9baa713d5b77fc060120de
--- /dev/null
+++ b/openpi_runtime/openpi/models/pi0.py
@@ -0,0 +1,279 @@
+import logging
+
+import einops
+import flax.nnx as nnx
+import flax.nnx.bridge as nnx_bridge
+import jax
+import jax.numpy as jnp
+from typing_extensions import override
+
+from openpi.models import model as _model
+from openpi.models import pi0_config
+import openpi.models.gemma as _gemma
+import openpi.models.siglip as _siglip
+from openpi.shared import array_typing as at
+
+logger = logging.getLogger("openpi")
+
+
+def make_attn_mask(input_mask, mask_ar):
+    """Adapted from big_vision.
+
+    Tokens can attend to valid inputs tokens which have a cumulative mask_ar
+    smaller or equal to theirs. This way `mask_ar` bool[?B, N] can be used to
+    setup several types of attention, for example:
+
+      [[1 1 1 1 1 1]]: pure causal attention.
+
+      [[0 0 0 1 1 1]]: prefix-lm attention. The first 3 tokens can attend between
+          themselves and the last 3 tokens have a causal attention. The first
+          entry could also be a 1 without changing behaviour.
+
+      [[1 0 1 0 1 0 0 1 0 0]]: causal attention between 4 blocks. Tokens of a
+          block can attend all previous blocks and all tokens on the same block.
+
+    Args:
+      input_mask: bool[B, N] true if its part of the input, false if padding.
+      mask_ar: bool[?B, N] mask that's true where previous tokens cannot depend on
+        it and false where it shares the same attention mask as the previous token.
+    """
+    mask_ar = jnp.broadcast_to(mask_ar, input_mask.shape)
+    cumsum = jnp.cumsum(mask_ar, axis=1)
+    attn_mask = cumsum[:, None, :] <= cumsum[:, :, None]
+    valid_mask = input_mask[:, None, :] * input_mask[:, :, None]
+    return jnp.logical_and(attn_mask, valid_mask)
+
+
+@at.typecheck
+def posemb_sincos(
+    pos: at.Real[at.Array, " b"], embedding_dim: int, min_period: float, max_period: float
+) -> at.Float[at.Array, "b {embedding_dim}"]:
+    """Computes sine-cosine positional embedding vectors for scalar positions."""
+    if embedding_dim % 2 != 0:
+        raise ValueError(f"embedding_dim ({embedding_dim}) must be divisible by 2")
+
+    fraction = jnp.linspace(0.0, 1.0, embedding_dim // 2)
+    period = min_period * (max_period / min_period) ** fraction
+    sinusoid_input = jnp.einsum(
+        "i,j->ij",
+        pos,
+        1.0 / period * 2 * jnp.pi,
+        precision=jax.lax.Precision.HIGHEST,
+    )
+    return jnp.concatenate([jnp.sin(sinusoid_input), jnp.cos(sinusoid_input)], axis=-1)
+
+
+class Pi0(_model.BaseModel):
+    def __init__(self, config: pi0_config.Pi0Config, rngs: nnx.Rngs):
+        super().__init__(config.action_dim, config.action_horizon, config.max_token_len)
+        self.pi05 = config.pi05
+        paligemma_config = _gemma.get_config(config.paligemma_variant)
+        action_expert_config = _gemma.get_config(config.action_expert_variant)
+        # TODO: rewrite gemma in NNX. For now, use bridge.
+        llm = nnx_bridge.ToNNX(
+            _gemma.Module(
+                configs=[paligemma_config, action_expert_config],
+                embed_dtype=config.dtype,
+                adarms=config.pi05,
+            )
+        )
+        llm.lazy_init(rngs=rngs, method="init", use_adarms=[False, True] if config.pi05 else [False, False])
+        img = nnx_bridge.ToNNX(
+            _siglip.Module(
+                num_classes=paligemma_config.width,
+                variant="So400m/14",
+                pool_type="none",
+                scan=True,
+                dtype_mm=config.dtype,
+            )
+        )
+        img.lazy_init(next(iter(config.fake_obs().images.values())), train=False, rngs=rngs)
+        self.PaliGemma = nnx.Dict(llm=llm, img=img)
+        self.action_in_proj = nnx.Linear(config.action_dim, action_expert_config.width, rngs=rngs)
+        if config.pi05:
+            self.time_mlp_in = nnx.Linear(action_expert_config.width, action_expert_config.width, rngs=rngs)
+            self.time_mlp_out = nnx.Linear(action_expert_config.width, action_expert_config.width, rngs=rngs)
+        else:
+            self.state_proj = nnx.Linear(config.action_dim, action_expert_config.width, rngs=rngs)
+            self.action_time_mlp_in = nnx.Linear(2 * action_expert_config.width, action_expert_config.width, rngs=rngs)
+            self.action_time_mlp_out = nnx.Linear(action_expert_config.width, action_expert_config.width, rngs=rngs)
+        self.action_out_proj = nnx.Linear(action_expert_config.width, config.action_dim, rngs=rngs)
+
+        # This attribute gets automatically set by model.train() and model.eval().
+        self.deterministic = True
+
+    @at.typecheck
+    def embed_prefix(
+        self, obs: _model.Observation
+    ) -> tuple[at.Float[at.Array, "b s emb"], at.Bool[at.Array, "b s"], at.Bool[at.Array, " s"]]:
+        input_mask = []
+        ar_mask = []
+        tokens = []
+        # embed images
+        for name in obs.images:
+            image_tokens, _ = self.PaliGemma.img(obs.images[name], train=False)
+
+            tokens.append(image_tokens)
+            input_mask.append(
+                einops.repeat(
+                    obs.image_masks[name],
+                    "b -> b s",
+                    s=image_tokens.shape[1],
+                )
+            )
+            # image tokens attend to each other
+            ar_mask += [False] * image_tokens.shape[1]
+
+        # add language (aka tokenized inputs)
+        if obs.tokenized_prompt is not None:
+            tokenized_inputs = self.PaliGemma.llm(obs.tokenized_prompt, method="embed")
+            tokens.append(tokenized_inputs)
+            input_mask.append(obs.tokenized_prompt_mask)
+            # full attention between image and language inputs
+            ar_mask += [False] * tokenized_inputs.shape[1]
+        tokens = jnp.concatenate(tokens, axis=1)
+        input_mask = jnp.concatenate(input_mask, axis=1)
+        ar_mask = jnp.array(ar_mask)
+        return tokens, input_mask, ar_mask
+
+    @at.typecheck
+    def embed_suffix(
+        self, obs: _model.Observation, noisy_actions: _model.Actions, timestep: at.Float[at.Array, " b"]
+    ) -> tuple[
+        at.Float[at.Array, "b s emb"],
+        at.Bool[at.Array, "b s"],
+        at.Bool[at.Array, " s"],
+        at.Float[at.Array, "b emb"] | None,
+    ]:
+        input_mask = []
+        ar_mask = []
+        tokens = []
+        if not self.pi05:
+            # add a single state token
+            state_token = self.state_proj(obs.state)[:, None, :]
+            tokens.append(state_token)
+            input_mask.append(jnp.ones((obs.state.shape[0], 1), dtype=jnp.bool_))
+            # image/language inputs do not attend to state or actions
+            ar_mask += [True]
+
+        action_tokens = self.action_in_proj(noisy_actions)
+        # embed timestep using sine-cosine positional encoding with sensitivity in the range [0, 1]
+        time_emb = posemb_sincos(timestep, self.action_in_proj.out_features, min_period=4e-3, max_period=4.0)
+        if self.pi05:
+            # time MLP (for adaRMS)
+            time_emb = self.time_mlp_in(time_emb)
+            time_emb = nnx.swish(time_emb)
+            time_emb = self.time_mlp_out(time_emb)
+            time_emb = nnx.swish(time_emb)
+            action_expert_tokens = action_tokens
+            adarms_cond = time_emb
+        else:
+            # mix timestep + action information using an MLP (no adaRMS)
+            time_tokens = einops.repeat(time_emb, "b emb -> b s emb", s=self.action_horizon)
+            action_time_tokens = jnp.concatenate([action_tokens, time_tokens], axis=-1)
+            action_time_tokens = self.action_time_mlp_in(action_time_tokens)
+            action_time_tokens = nnx.swish(action_time_tokens)
+            action_time_tokens = self.action_time_mlp_out(action_time_tokens)
+            action_expert_tokens = action_time_tokens
+            adarms_cond = None
+        tokens.append(action_expert_tokens)
+        input_mask.append(jnp.ones(action_expert_tokens.shape[:2], dtype=jnp.bool_))
+        # image/language/state inputs do not attend to action tokens
+        ar_mask += [True] + ([False] * (self.action_horizon - 1))
+        tokens = jnp.concatenate(tokens, axis=1)
+        input_mask = jnp.concatenate(input_mask, axis=1)
+        ar_mask = jnp.array(ar_mask)
+        return tokens, input_mask, ar_mask, adarms_cond
+
+    @override
+    def compute_loss(
+        self, rng: at.KeyArrayLike, observation: _model.Observation, actions: _model.Actions, *, train: bool = False
+    ) -> at.Float[at.Array, "*b ah"]:
+        preprocess_rng, noise_rng, time_rng = jax.random.split(rng, 3)
+        observation = _model.preprocess_observation(preprocess_rng, observation, train=train)
+
+        batch_shape = actions.shape[:-2]
+        noise = jax.random.normal(noise_rng, actions.shape)
+        time = jax.random.beta(time_rng, 1.5, 1, batch_shape) * 0.999 + 0.001
+        time_expanded = time[..., None, None]
+        x_t = time_expanded * noise + (1 - time_expanded) * actions
+        u_t = noise - actions
+
+        # one big forward pass of prefix + suffix at once
+        prefix_tokens, prefix_mask, prefix_ar_mask = self.embed_prefix(observation)
+        suffix_tokens, suffix_mask, suffix_ar_mask, adarms_cond = self.embed_suffix(observation, x_t, time)
+        input_mask = jnp.concatenate([prefix_mask, suffix_mask], axis=1)
+        ar_mask = jnp.concatenate([prefix_ar_mask, suffix_ar_mask], axis=0)
+        attn_mask = make_attn_mask(input_mask, ar_mask)
+        positions = jnp.cumsum(input_mask, axis=1) - 1
+        (prefix_out, suffix_out), _ = self.PaliGemma.llm(
+            [prefix_tokens, suffix_tokens], mask=attn_mask, positions=positions, adarms_cond=[None, adarms_cond]
+        )
+        v_t = self.action_out_proj(suffix_out[:, -self.action_horizon :])
+
+        return jnp.mean(jnp.square(v_t - u_t), axis=-1)
+
+    @override
+    def sample_actions(
+        self,
+        rng: at.KeyArrayLike,
+        observation: _model.Observation,
+        *,
+        num_steps: int | at.Int[at.Array, ""] = 10,
+        noise: at.Float[at.Array, "b ah ad"] | None = None,
+    ) -> _model.Actions:
+        observation = _model.preprocess_observation(None, observation, train=False)
+        # note that we use the convention more common in diffusion literature, where t=1 is noise and t=0 is the target
+        # distribution. yes, this is the opposite of the pi0 paper, and I'm sorry.
+        dt = -1.0 / num_steps
+        batch_size = observation.state.shape[0]
+        if noise is None:
+            noise = jax.random.normal(rng, (batch_size, self.action_horizon, self.action_dim))
+
+        # first fill KV cache with a forward pass of the prefix
+        prefix_tokens, prefix_mask, prefix_ar_mask = self.embed_prefix(observation)
+        prefix_attn_mask = make_attn_mask(prefix_mask, prefix_ar_mask)
+        positions = jnp.cumsum(prefix_mask, axis=1) - 1
+        _, kv_cache = self.PaliGemma.llm([prefix_tokens, None], mask=prefix_attn_mask, positions=positions)
+
+        def step(carry):
+            x_t, time = carry
+            suffix_tokens, suffix_mask, suffix_ar_mask, adarms_cond = self.embed_suffix(
+                observation, x_t, jnp.broadcast_to(time, batch_size)
+            )
+            # `suffix_attn_mask` is shape (b, suffix_len, suffix_len) indicating how the suffix tokens can attend to each
+            # other
+            suffix_attn_mask = make_attn_mask(suffix_mask, suffix_ar_mask)
+            # `prefix_attn_mask` is shape (b, suffix_len, prefix_len) indicating how the suffix tokens can attend to the
+            # prefix tokens
+            prefix_attn_mask = einops.repeat(prefix_mask, "b p -> b s p", s=suffix_tokens.shape[1])
+            # `combined_mask` is shape (b, suffix_len, prefix_len + suffix_len) indicating how the suffix tokens (which
+            # generate the queries) can attend to the full prefix + suffix sequence (which generates the keys and values)
+            full_attn_mask = jnp.concatenate([prefix_attn_mask, suffix_attn_mask], axis=-1)
+            assert full_attn_mask.shape == (
+                batch_size,
+                suffix_tokens.shape[1],
+                prefix_tokens.shape[1] + suffix_tokens.shape[1],
+            )
+            # `positions` is shape (b, suffix_len) indicating the positions of the suffix tokens
+            positions = jnp.sum(prefix_mask, axis=-1)[:, None] + jnp.cumsum(suffix_mask, axis=-1) - 1
+
+            (prefix_out, suffix_out), _ = self.PaliGemma.llm(
+                [None, suffix_tokens],
+                mask=full_attn_mask,
+                positions=positions,
+                kv_cache=kv_cache,
+                adarms_cond=[None, adarms_cond],
+            )
+            assert prefix_out is None
+            v_t = self.action_out_proj(suffix_out[:, -self.action_horizon :])
+
+            return x_t + dt * v_t, time + dt
+
+        def cond(carry):
+            x_t, time = carry
+            # robust to floating-point error
+            return time >= -dt / 2
+
+        x_0, _ = jax.lax.while_loop(cond, step, (noise, 1.0))
+        return x_0
diff --git a/openpi_runtime/openpi/models/pi0_config.py b/openpi_runtime/openpi/models/pi0_config.py
new file mode 100644
index 0000000000000000000000000000000000000000..584d83f199e092203b59861a861c64768a4e0300
--- /dev/null
+++ b/openpi_runtime/openpi/models/pi0_config.py
@@ -0,0 +1,117 @@
+import dataclasses
+from typing import TYPE_CHECKING
+
+import flax.nnx as nnx
+import jax
+import jax.numpy as jnp
+from typing_extensions import override
+
+from openpi.models import model as _model
+import openpi.models.gemma as _gemma
+from openpi.shared import array_typing as at
+import openpi.shared.nnx_utils as nnx_utils
+
+if TYPE_CHECKING:
+    from openpi.models.pi0 import Pi0
+
+
+@dataclasses.dataclass(frozen=True)
+class Pi0Config(_model.BaseModelConfig):
+    dtype: str = "bfloat16"
+    paligemma_variant: _gemma.Variant = "gemma_2b"
+    action_expert_variant: _gemma.Variant = "gemma_300m"
+
+    # Set the model specific defaults.
+    action_dim: int = 32
+    action_horizon: int = 50
+    max_token_len: int = None  # type: ignore
+    # Pi05 has two differences from Pi0:
+    # - the state input is part of the discrete language tokens rather than a continuous input that is part of the suffix
+    # - the action expert uses adaRMSNorm to inject the flow matching timestep
+    pi05: bool = False
+    # This config option is not used directly by the model, but it is read by the ModelTransformFactory.
+    discrete_state_input: bool = None  # type: ignore
+
+    pytorch_compile_mode: str | None = "max-autotune"
+
+    def __post_init__(self):
+        if self.max_token_len is None:
+            object.__setattr__(self, "max_token_len", 200 if self.pi05 else 48)
+        if self.discrete_state_input is None:
+            object.__setattr__(self, "discrete_state_input", self.pi05)
+        if self.pytorch_compile_mode is not None:
+            assert self.pytorch_compile_mode in [
+                "default",
+                "reduce-overhead",
+                "max-autotune",
+                "max-autotune-no-cudagraphs",
+            ]
+
+    @property
+    @override
+    def model_type(self) -> _model.ModelType:
+        if self.pi05:
+            return _model.ModelType.PI05
+        return _model.ModelType.PI0
+
+    @override
+    def create(self, rng: at.KeyArrayLike) -> "Pi0":
+        from openpi.models.pi0 import Pi0
+
+        return Pi0(self, rngs=nnx.Rngs(rng))
+
+    @override
+    def inputs_spec(self, *, batch_size: int = 1) -> tuple[_model.Observation, _model.Actions]:
+        image_spec = jax.ShapeDtypeStruct([batch_size, *_model.IMAGE_RESOLUTION, 3], jnp.float32)
+        image_mask_spec = jax.ShapeDtypeStruct([batch_size], jnp.bool_)
+
+        with at.disable_typechecking():
+            observation_spec = _model.Observation(
+                images={
+                    "base_0_rgb": image_spec,
+                    "left_wrist_0_rgb": image_spec,
+                    "right_wrist_0_rgb": image_spec,
+                },
+                image_masks={
+                    "base_0_rgb": image_mask_spec,
+                    "left_wrist_0_rgb": image_mask_spec,
+                    "right_wrist_0_rgb": image_mask_spec,
+                },
+                state=jax.ShapeDtypeStruct([batch_size, self.action_dim], jnp.float32),
+                tokenized_prompt=jax.ShapeDtypeStruct([batch_size, self.max_token_len], jnp.int32),
+                tokenized_prompt_mask=jax.ShapeDtypeStruct([batch_size, self.max_token_len], bool),
+            )
+        action_spec = jax.ShapeDtypeStruct([batch_size, self.action_horizon, self.action_dim], jnp.float32)
+
+        return observation_spec, action_spec
+
+    def get_freeze_filter(self) -> nnx.filterlib.Filter:
+        """Returns the freeze filter based on the model config."""
+        filters = []
+        has_lora = False
+        gemma_params_filter = nnx_utils.PathRegex(".*llm.*")
+        action_expert_params_filter = nnx_utils.PathRegex(".*llm.*_1.*")
+        if "lora" in self.paligemma_variant:
+            filters.append(
+                gemma_params_filter,
+            )
+            if "lora" not in self.action_expert_variant:
+                # If only freeze gemma params, exclude action expert params.
+                filters.append(
+                    nnx.Not(action_expert_params_filter),
+                )
+            has_lora = True
+        elif "lora" in self.action_expert_variant:
+            filters.append(
+                action_expert_params_filter,
+            )
+            has_lora = True
+
+        if has_lora:
+            # If any lora is used, exclude all lora params.
+            filters.append(
+                nnx.Not(nnx_utils.PathRegex(".*lora.*")),
+            )
+        if not filters:
+            return nnx.Nothing
+        return nnx.All(*filters)
diff --git a/openpi_runtime/openpi/models/pi0_fast.py b/openpi_runtime/openpi/models/pi0_fast.py
new file mode 100644
index 0000000000000000000000000000000000000000..e6b5bd15e27a58a37e8db3f9f9b9707806fec7a5
--- /dev/null
+++ b/openpi_runtime/openpi/models/pi0_fast.py
@@ -0,0 +1,313 @@
+import dataclasses
+import logging
+from typing import Any
+
+import einops
+import flax.nnx as nnx
+import flax.nnx.bridge as nnx_bridge
+import jax
+import jax.numpy as jnp
+from typing_extensions import override
+
+from openpi.models import model as _model
+import openpi.models.gemma_fast as _gemma
+import openpi.models.siglip as _siglip
+from openpi.shared import array_typing as at
+import openpi.shared.nnx_utils as nnx_utils
+
+logger = logging.getLogger("openpi")
+
+PALIGEMMA_EOS_TOKEN = 1
+
+
+def make_attn_mask(input_mask, mask_ar):
+    """Adapted from big_vision.
+
+    Tokens can attend to valid inputs tokens which have a cumulative mask_ar
+    smaller or equal to theirs. This way `mask_ar` bool[?B, N] can be used to
+    setup several types of attention, for example:
+
+      [[1 1 1 1 1 1]]: pure causal attention.
+
+      [[0 0 0 1 1 1]]: prefix-lm attention. The first 3 tokens can attend between
+          themselves and the last 3 tokens have a causal attention. The first
+          entry could also be a 1 without changing behaviour.
+
+      [[1 0 1 0 1 0 0 1 0 0]]: causal attention between 4 blocks. Tokens of a
+          block can attend all previous blocks and all tokens on the same block.
+
+    Args:
+      input_mask: bool[B, N] true if its part of the input, false if padding.
+      mask_ar: bool[?B, N] mask that's true where previous tokens cannot depend on
+        it and false where it shares the same attention mask as the previous token.
+    """
+    mask_ar = jnp.broadcast_to(mask_ar, input_mask.shape)
+    cumsum = jnp.cumsum(mask_ar, axis=1)
+    attn_mask = cumsum[:, None, :] <= cumsum[:, :, None]
+    valid_mask = input_mask[:, None, :] * input_mask[:, :, None]
+    return jnp.logical_and(attn_mask, valid_mask)
+
+
+@jax.vmap
+def left_to_right_align(x, input_mask, attn_mask):
+    """Converts input from left-align to right-aligned."""
+    # Due to vmap, this is operating in a single example (not batch level).
+    assert x.ndim == 2
+    assert input_mask.ndim == 1
+    assert attn_mask.ndim == 2
+    assert x.shape[0] == input_mask.shape[0]
+    assert attn_mask.shape[0] == attn_mask.shape[1], attn_mask.shape
+    seqlen = jnp.max(input_mask * jnp.arange(input_mask.shape[0])) + 1
+    x = jnp.roll(x, -seqlen, axis=0)
+    input_mask = jnp.roll(input_mask, -seqlen, axis=0)
+    attn_mask = jnp.roll(attn_mask, -seqlen, axis=(0, 1))
+    return x, input_mask, attn_mask
+
+
+def put_along_last_axis(arr, indices, values):
+    """Like np.put_along_axis(..., axis=-1), since jax is missing it."""
+    assert arr.ndim == indices.ndim == values.ndim, (arr.ndim, indices.ndim, values.ndim)
+    onehot = jax.nn.one_hot(indices, arr.shape[-1], dtype=values.dtype)
+    put_mask = jnp.einsum("...i,...in->...n", jnp.ones(values.shape, jnp.int32), onehot)
+    put_values = jnp.einsum("...i,...in->...n", values, onehot)
+    return jnp.where(put_mask, put_values, arr)
+
+
+@dataclasses.dataclass(frozen=True)
+class Pi0FASTConfig(_model.BaseModelConfig):
+    dtype: str = "bfloat16"
+    paligemma_variant: _gemma.Variant = "gemma_2b"
+
+    # Set the model specific defaults.
+    action_dim: int = 32
+    action_horizon: int = 32
+    max_token_len: int = 250
+
+    # Tokenizer for the fast model.
+    fast_model_tokenizer: Any | None = None
+    # Keyword arguments for the fast model tokenizer.
+    fast_model_tokenizer_kwargs: dict[str, Any] | None = None
+
+    @property
+    @override
+    def model_type(self) -> _model.ModelType:
+        return _model.ModelType.PI0_FAST
+
+    @override
+    def create(self, rng: at.KeyArrayLike) -> "Pi0FAST":
+        return Pi0FAST(self, rngs=nnx.Rngs(rng))
+
+    @override
+    def inputs_spec(self, *, batch_size: int = 1) -> tuple[_model.Observation, _model.Actions]:
+        image_spec = jax.ShapeDtypeStruct([batch_size, *_model.IMAGE_RESOLUTION, 3], jnp.float32)
+        image_mask_spec = jax.ShapeDtypeStruct([batch_size], jnp.bool_)
+
+        with at.disable_typechecking():
+            observation_spec = _model.Observation(
+                images={
+                    "base_0_rgb": image_spec,
+                    "base_1_rgb": image_spec,
+                    "wrist_0_rgb": image_spec,
+                },
+                image_masks={
+                    "base_0_rgb": image_mask_spec,
+                    "base_1_rgb": image_mask_spec,
+                    "wrist_0_rgb": image_mask_spec,
+                },
+                state=jax.ShapeDtypeStruct([batch_size, self.action_dim], jnp.float32),
+                tokenized_prompt=jax.ShapeDtypeStruct([batch_size, self.max_token_len], jnp.int32),
+                tokenized_prompt_mask=jax.ShapeDtypeStruct([batch_size, self.max_token_len], bool),
+                token_ar_mask=jax.ShapeDtypeStruct([batch_size, self.max_token_len], jnp.int32),
+                token_loss_mask=jax.ShapeDtypeStruct([batch_size, self.max_token_len], jnp.bool_),
+            )
+        action_spec = jax.ShapeDtypeStruct([batch_size, self.action_horizon, self.action_dim], jnp.float32)
+
+        return observation_spec, action_spec
+
+    def get_freeze_filter(self) -> nnx.filterlib.Filter:
+        """Returns the freeze filter based on the model config."""
+        if "lora" in self.paligemma_variant:
+            return nnx.All(nnx_utils.PathRegex(".*llm.*"), nnx.Not(nnx_utils.PathRegex(".*lora.*")))
+        return nnx.Nothing
+
+
+class Pi0FAST(_model.BaseModel):
+    def __init__(self, config: Pi0FASTConfig, rngs: nnx.Rngs):
+        super().__init__(config.action_dim, config.action_horizon, config.max_token_len)
+        paligemma_config = _gemma.get_config(config.paligemma_variant)
+        # TODO: rewrite gemma in NNX. For now, use bridge.
+        llm = nnx_bridge.ToNNX(
+            _gemma.Module(
+                **paligemma_config,
+                embed_dtype=config.dtype,
+                cache_dtype=config.dtype,
+            )
+        )
+        llm.lazy_init(rngs=rngs, method="init")
+        img = nnx_bridge.ToNNX(
+            _siglip.Module(
+                num_classes=paligemma_config.width,
+                variant="So400m/14",
+                pool_type="none",
+                scan=True,
+                dtype_mm=config.dtype,
+            )
+        )
+        img.lazy_init(next(iter(config.fake_obs().images.values())), train=False, rngs=rngs)
+        self.PaliGemma = nnx.Dict(llm=llm, img=img)
+
+    @at.typecheck
+    def embed_inputs(
+        self, obs: _model.Observation
+    ) -> tuple[at.Float[at.Array, "b s emb"], at.Bool[at.Array, "b s"], at.Int[at.Array, "b s"]]:
+        input_mask = []
+        ar_mask = []
+        token_embeddings = []
+        # embed images
+        for name in obs.images:
+            image_token_embeddings, _ = self.PaliGemma.img(obs.images[name], train=False)
+
+            token_embeddings.append(image_token_embeddings)
+            input_mask.append(
+                einops.repeat(
+                    obs.image_masks[name],
+                    "b -> b s",
+                    s=image_token_embeddings.shape[1],
+                )
+            )
+            # image tokens attend to each other --> AR mask = 0
+            ar_mask.append(0 * input_mask[-1])
+
+        # add tokenized inputs
+        assert obs.tokenized_prompt is not None, "Tokenized prompt is required"
+        assert obs.tokenized_prompt_mask is not None, "Tokenized prompt mask is required"
+        assert obs.token_ar_mask is not None, "Token auto-regressive mask is required"
+        tokenized_inputs_embeddings = self.PaliGemma.llm(obs.tokenized_prompt, embed_only=True)
+        token_embeddings.append(tokenized_inputs_embeddings)
+        input_mask.append(obs.tokenized_prompt_mask)
+        ar_mask.append(obs.token_ar_mask)
+
+        # return embeddings, input mask, and ar mask
+        return (
+            jnp.concatenate(token_embeddings, axis=1),
+            jnp.concatenate(input_mask, axis=1),
+            jnp.concatenate(ar_mask, axis=1),
+        )
+
+    @override
+    def compute_loss(
+        self, rng: at.KeyArrayLike, observation: _model.Observation, actions: _model.Actions, *, train: bool = False
+    ) -> at.Float[at.Array, "*b ah"]:
+        observation = _model.preprocess_observation(
+            rng, observation, train=train, image_keys=list(observation.images.keys())
+        )
+
+        # Compute inputs: one big forward pass of prefix + suffix at once
+        input_token_embeddings, input_mask, ar_mask = self.embed_inputs(observation)
+        attn_mask = make_attn_mask(input_mask, ar_mask)
+
+        # Compute one-hot targets: we predict *next* token, so shift the input tokens by one.
+        targets = jax.nn.one_hot(
+            observation.tokenized_prompt[:, 1:],
+            self.PaliGemma.llm.module.vocab_size,
+        )
+
+        # Each input predicts *next* token, so we don't input the last token.
+        pre_logits, _, _ = self.PaliGemma.llm(
+            embedded_prefix=input_token_embeddings[:, :-1],
+            mask=attn_mask[:, :-1, :-1],
+            return_prelogits=True,
+        )
+
+        # Only decode logits for the target tokens to save memory
+        # (decoding matmul is large because it is a seq_len x vocab_size dense layer).
+        logits, _ = self.PaliGemma.llm(
+            pre_logits=pre_logits[:, -targets.shape[1] :],
+        )
+        logp = jax.nn.log_softmax(logits, axis=-1)
+
+        # Compute CE loss on token targets
+        assert observation.token_loss_mask is not None, "Token loss mask is required"
+        loss_mask = observation.token_loss_mask[:, 1:]
+        token_pplx = jnp.sum(targets * logp, axis=-1)
+        return -jnp.sum(token_pplx * loss_mask, axis=-1) / jnp.clip(jnp.sum(loss_mask, -1), 1)
+
+    @override
+    def sample_actions(
+        self,
+        rng: at.KeyArrayLike,
+        observation: _model.Observation,
+        *,
+        max_decoding_steps: int | at.Int[at.Array, ""] = 256,
+        temperature: float = 0.0,
+    ) -> _model.Actions:
+        # TODO: this is a hack to get the image keys.
+        observation = _model.preprocess_observation(
+            None, observation, train=False, image_keys=list(observation.images.keys())
+        )
+
+        # embed inputs
+        prefix_token_embeddings, prefix_mask, prefix_ar_mask = self.embed_inputs(observation)
+        prefix_attn_mask = make_attn_mask(prefix_mask, prefix_ar_mask)
+
+        # left to right align all input token sequences
+        prefix_token_embeddings, prefix_mask, prefix_attn_mask = left_to_right_align(
+            prefix_token_embeddings, prefix_mask, prefix_attn_mask
+        )
+        prefill_size = prefix_token_embeddings.shape[1]
+        prefill_len = jnp.sum(prefix_mask, axis=-1)
+        prefix_start = prefill_size - prefill_len
+
+        # first fill KV cache with a forward pass of the prefix
+        # pad attention mask to set the size of the KV cache (prefill_size + max_decoding_steps)
+        prefix_attn_mask = jnp.pad(prefix_attn_mask, ((0, 0), (0, 0), (0, max_decoding_steps)))
+        prefix_positions = jnp.cumsum(prefix_mask, axis=-1) - 1
+        prefix_logits, kv_cache, _ = self.PaliGemma.llm(
+            embedded_prefix=prefix_token_embeddings, mask=prefix_attn_mask, positions=prefix_positions, decode=True
+        )
+
+        # prepare decoding -- final logit decodes the first token
+        last_logit = prefix_logits[:, -1:]
+        output_tokens = jnp.zeros((last_logit.shape[0], max_decoding_steps))
+
+        def step(carry):
+            rng, last_logit, output_tokens, cache, _, step = carry
+
+            # Sample token from last logit
+            # Split RNG for this step
+            rng, rng_step = jax.random.split(rng)
+            token = jax.lax.cond(
+                temperature > 0.0,
+                lambda _: jax.random.categorical(rng_step, last_logit / temperature, axis=-1),
+                lambda _: jnp.argmax(last_logit, axis=-1),
+                operand=None,
+            )
+            output_tokens = put_along_last_axis(output_tokens, jnp.broadcast_to(step, (token.shape[0], 1)), token)
+
+            # Check for early stopping --> stop if all batch elements have EOS token
+            has_eos = jnp.any(token == PALIGEMMA_EOS_TOKEN, axis=-1)
+            all_eos = jnp.all(has_eos)
+
+            # Decode one step
+            token_embedding = self.PaliGemma.llm(token, embed_only=True)
+            positions = prefill_len[:, None] + step + 1
+            mask = jnp.logical_and(
+                jnp.arange(prefill_size + max_decoding_steps)[None, None, :] >= prefix_start[:, None, None],
+                jnp.arange(prefill_size + max_decoding_steps)[None, None, :]
+                < (jnp.broadcast_to(prefill_size + step + 1, (prefix_start.shape[0], 1, 1))),
+            )
+            last_logit, kv_cache, _ = self.PaliGemma.llm(
+                embedded_prefix=token_embedding, mask=mask, positions=positions, decode=True, kv_cache=cache
+            )
+
+            return rng, last_logit, output_tokens, kv_cache, all_eos, step + 1
+
+        def cond(carry):
+            _, _, _, _, all_eos, step = carry
+            return (~all_eos) & (step < max_decoding_steps)
+
+        # Use lax.while_loop so we can jit the full decoding loop.
+        _, _, output_tokens, _, _, _ = jax.lax.while_loop(
+            cond, step, (rng, last_logit, output_tokens, kv_cache, False, 0)
+        )
+        return output_tokens
diff --git a/openpi_runtime/openpi/models/siglip.py b/openpi_runtime/openpi/models/siglip.py
new file mode 100644
index 0000000000000000000000000000000000000000..c74c99e75fa45308fcadff115a7fd4ed12c9e96c
--- /dev/null
+++ b/openpi_runtime/openpi/models/siglip.py
@@ -0,0 +1,373 @@
+# Copyright 2024 Big Vision Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""A refactored and simplified ViT adoptation for Pi, taken from big_vision."""
+
+from collections.abc import Sequence
+
+import flax.linen as nn
+import jax
+import jax.numpy as jnp
+import numpy as np
+
+import openpi.training.sharding as sharding
+
+
+def posemb_sincos_2d(h, w, width, temperature=10_000.0, dtype=jnp.float32):
+    """Follows the MoCo v3 logic."""
+    y, x = jnp.mgrid[:h, :w]
+
+    assert width % 4 == 0, "Width must be mult of 4 for sincos posemb"
+    omega = jnp.arange(width // 4) / (width // 4 - 1)
+    omega = 1.0 / (temperature**omega)
+    y = jnp.einsum("m,d->md", y.flatten(), omega)
+    x = jnp.einsum("m,d->md", x.flatten(), omega)
+    pe = jnp.concatenate([jnp.sin(x), jnp.cos(x), jnp.sin(y), jnp.cos(y)], axis=1)
+    return jnp.asarray(pe, dtype)[None, :, :]
+
+
+def get_posemb(self, typ, seqshape, width, name, dtype=jnp.float32):
+    if typ == "learn":
+        return self.param(
+            name,
+            nn.initializers.normal(stddev=1 / np.sqrt(width)),
+            (1, np.prod(seqshape), width),
+            dtype,
+        )
+    if typ == "sincos2d":
+        return posemb_sincos_2d(*seqshape, width, dtype=dtype)
+    raise ValueError(f"Unknown posemb type: {typ}")
+
+
+class MlpBlock(nn.Module):
+    """Transformer MLP / feed-forward block."""
+
+    mlp_dim: int | None = None  # Defaults to 4x input dim
+    dropout: float = 0.0
+    dtype_mm: str = "float32"
+
+    @nn.compact
+    def __call__(self, x, deterministic=True):  # noqa: FBT002
+        """Applies Transformer MlpBlock module."""
+        inits = {
+            "kernel_init": nn.initializers.xavier_uniform(),
+            "bias_init": nn.initializers.normal(stddev=1e-6),
+        }
+
+        _, _, d = x.shape  # n,l,d
+        x = nn.Dense(self.mlp_dim or 4 * d, dtype=self.dtype_mm, **inits)(x)
+        x = nn.gelu(x)
+        x = nn.Dropout(rate=self.dropout)(x, deterministic)
+        return nn.Dense(d, dtype=self.dtype_mm, **inits)(x)
+
+
+class Encoder1DBlock(nn.Module):
+    """Single transformer encoder block (MHSA + MLP)."""
+
+    mlp_dim: int | None = None  # Defaults to 4x input dim
+    num_heads: int = 12
+    dropout: float = 0.0
+    dtype_mm: str = "float32"
+
+    @nn.compact
+    def __call__(self, x, deterministic=True):  # noqa: FBT002
+        out = {}
+        x = sharding.activation_sharding_constraint(x)
+        y = nn.LayerNorm(dtype=self.dtype_mm)(x)
+        y = out["sa"] = nn.MultiHeadDotProductAttention(
+            num_heads=self.num_heads,
+            kernel_init=nn.initializers.xavier_uniform(),
+            deterministic=deterministic,
+            dtype=self.dtype_mm,
+        )(y, y)
+        y = sharding.activation_sharding_constraint(y)
+        y = nn.Dropout(rate=self.dropout)(y, deterministic)
+        x = out["+sa"] = x + y
+
+        y = nn.LayerNorm(dtype=self.dtype_mm)(x)
+        y = out["mlp"] = MlpBlock(
+            mlp_dim=self.mlp_dim,
+            dropout=self.dropout,
+            dtype_mm=self.dtype_mm,
+        )(y, deterministic)
+        y = sharding.activation_sharding_constraint(y)
+        y = nn.Dropout(rate=self.dropout)(y, deterministic)
+        x = out["+mlp"] = x + y
+        x = sharding.activation_sharding_constraint(x)
+        return x, out
+
+
+class Encoder(nn.Module):
+    """Transformer Model Encoder for sequence to sequence translation."""
+
+    depth: int
+    mlp_dim: int | None = None  # Defaults to 4x input dim
+    num_heads: int = 12
+    dropout: float = 0.0
+    scan: bool = False
+    remat_policy: str = "nothing_saveable"
+    dtype_mm: str = "float32"
+
+    @nn.compact
+    def __call__(self, x, deterministic=True):  # noqa: FBT002
+        out = {}
+
+        if self.scan:
+            block = nn.remat(
+                Encoder1DBlock,
+                prevent_cse=False,
+                static_argnums=(2,),  # 0=self, 2=deterministic
+                policy=getattr(jax.checkpoint_policies, self.remat_policy, None),
+            )
+            x, scan_out = nn.scan(
+                block,
+                variable_axes={"params": 0},
+                split_rngs={"params": True, "dropout": True},
+                in_axes=nn.broadcast,
+                length=self.depth,
+            )(
+                name="encoderblock",
+                dtype_mm=self.dtype_mm,
+                mlp_dim=self.mlp_dim,
+                num_heads=self.num_heads,
+                dropout=self.dropout,
+            )(x, deterministic)
+            for lyr in range(self.depth):
+                out[f"block{lyr:02d}"] = jax.tree.map(lambda o, lyr=lyr: o[lyr], scan_out)
+        else:
+            # Input Encoder
+            for lyr in range(self.depth):
+                block_cur = Encoder1DBlock(
+                    name=f"encoderblock_{lyr}",
+                    dtype_mm=self.dtype_mm,
+                    mlp_dim=self.mlp_dim,
+                    num_heads=self.num_heads,
+                    dropout=self.dropout,
+                )
+                x, out[f"block{lyr:02d}"] = block_cur(x, deterministic)
+            out["pre_ln"] = x  # Alias for last block, but without the number in it.
+
+        return nn.LayerNorm(name="encoder_norm", dtype=self.dtype_mm)(x), out
+
+
+class MAPHead(nn.Module):
+    """Multihead Attention Pooling."""
+
+    mlp_dim: int | None = None  # Defaults to 4x input dim
+    num_heads: int = 12
+    dtype_mm: str = "float32"
+
+    @nn.compact
+    def __call__(self, x):
+        n, _, d = x.shape  # n,l,d
+        probe = self.param("probe", nn.initializers.xavier_uniform(), (1, 1, d), x.dtype)
+        probe = jnp.tile(probe, [n, 1, 1])
+
+        x = nn.MultiHeadDotProductAttention(
+            num_heads=self.num_heads,
+            dtype=self.dtype_mm,
+            kernel_init=nn.initializers.xavier_uniform(),
+        )(probe, x)
+
+        y = nn.LayerNorm(dtype=self.dtype_mm)(x)
+        x = x + MlpBlock(mlp_dim=self.mlp_dim, dtype=self.dtype_mm)(y)
+        return x[:, 0]
+
+
+class _Module(nn.Module):
+    """ViT model."""
+
+    num_classes: int | None = None
+    patch_size: Sequence[int] = (16, 16)
+    width: int = 768
+    depth: int = 12
+    mlp_dim: int | None = None  # Defaults to 4x input dim
+    num_heads: int = 12
+    posemb: str = "learn"  # Can also be "sincos2d"
+    rep_size: int | bool = False
+    dropout: float = 0.0
+    pool_type: str = "gap"  # Can also be "map" or "tok"
+    head_zeroinit: bool = True
+    scan: bool = False
+    # or "dots_with_no_batch_dims_saveable" for more speed (memory costly)
+    remat_policy: str = "nothing_saveable"
+    dtype_mm: str = "float32"
+
+    @nn.compact
+    def __call__(self, image, *, train=False):
+        out = {}
+
+        # Kevin edit: do patch extraction and posemb in float32,
+        # because I feel like it's a bit safer.
+        image = jnp.asarray(image, jnp.float32)
+
+        # Patch extraction
+        x = out["stem"] = nn.Conv(
+            self.width,
+            self.patch_size,
+            strides=self.patch_size,
+            padding="VALID",
+            name="embedding",
+            dtype=jnp.float32,
+        )(image)
+
+        n, h, w, c = x.shape
+        x = jnp.reshape(x, [n, h * w, c])
+
+        # Add posemb before adding extra token.
+        x = out["with_posemb"] = x + get_posemb(self, self.posemb, (h, w), c, "pos_embedding", jnp.float32)
+
+        if self.pool_type == "tok":
+            cls = self.param("cls", nn.initializers.zeros, (1, 1, c), x.dtype)
+            x = jnp.concatenate([jnp.tile(cls, [n, 1, 1]), x], axis=1)
+
+        n, _, c = x.shape  # n,l,d
+        x = nn.Dropout(rate=self.dropout)(x, not train)
+
+        # Kevin edit: now cast back to dtype_mm (potentially half precision)
+        x = x.astype(self.dtype_mm)
+
+        x, out["encoder"] = Encoder(
+            depth=self.depth,
+            mlp_dim=self.mlp_dim,
+            num_heads=self.num_heads,
+            dropout=self.dropout,
+            scan=self.scan,
+            remat_policy=self.remat_policy,
+            dtype_mm=self.dtype_mm,
+            name="Transformer",
+        )(x, deterministic=not train)
+        encoded = out["encoded"] = x
+
+        if self.pool_type == "map":
+            x = out["head_input"] = MAPHead(
+                num_heads=self.num_heads,
+                mlp_dim=self.mlp_dim,
+                dtype=self.dtype_mm,
+            )(x)
+        elif self.pool_type == "gap":
+            x = out["head_input"] = jnp.mean(x, axis=1)
+        elif self.pool_type == "0":
+            x = out["head_input"] = x[:, 0]
+        elif self.pool_type == "tok":
+            x = out["head_input"] = x[:, 0]
+            encoded = encoded[:, 1:]
+        elif self.pool_type == "none":
+            pass
+        else:
+            raise ValueError(f"Unknown pool type: '{self.pool_type}'")
+
+        x_2d = jnp.reshape(encoded, [n, h, w, -1])
+
+        if self.rep_size:
+            rep_size = self.width if self.rep_size is True else self.rep_size
+            hid = nn.Dense(rep_size, dtype=self.dtype_mm, name="pre_logits")
+            # NOTE: In the past we did not include tanh in pre_logits.
+            # For few-shot, it should not matter much, as it whitens anyways.
+            x_2d = nn.tanh(hid(x_2d))
+            x = nn.tanh(hid(x))
+
+        out["pre_logits_2d"] = x_2d
+        out["pre_logits"] = x
+
+        if self.num_classes:
+            kw = {"kernel_init": nn.initializers.zeros} if self.head_zeroinit else {}
+            head = nn.Dense(self.num_classes, dtype=self.dtype_mm, name="head", **kw)
+            x_2d = out["logits_2d"] = head(x_2d)
+            x = out["logits"] = head(x)
+
+        return x, out
+
+
+def Module(num_classes=None, *, variant=None, **kw):  # pylint: disable=invalid-name  # noqa: N802
+    """Factory function, because linen really don't like what I'm doing!"""
+    return _Module(num_classes, **{**decode_variant(variant), **kw})
+
+
+def decode_variant(variant):
+    """Converts a string like "B" or "B/32" into a params dict."""
+    if variant is None:
+        return {}
+
+    v, patch = variant, {}
+    if "/" in variant:
+        v, patch = variant.split("/")
+        patch = {"patch_size": (int(patch), int(patch))}
+
+    return {
+        # pylint:disable=line-too-long
+        # Reference: Table 2 of https://arxiv.org/abs/2106.04560.
+        "width": {
+            "mu": 32,
+            "Ti": 192,
+            "S": 384,
+            "M": 512,
+            "B": 768,
+            "L": 1024,
+            "So400m": 1152,
+            "H": 1280,
+            "g": 1408,
+            "g-opt": 1536,
+            "G": 1664,
+            "G-opt": 1536,
+            "e": 1792,
+        }[v],
+        "depth": {
+            "mu": 1,
+            "Ti": 12,
+            "S": 12,
+            "M": 12,
+            "B": 12,
+            "L": 24,
+            "So400m": 27,
+            "H": 32,
+            "g": 40,
+            "g-opt": 40,
+            "G": 48,
+            "G-opt": 48,
+            "e": 56,
+        }[v],
+        "mlp_dim": {
+            "mu": 128,
+            "Ti": 768,
+            "S": 1536,
+            "M": 2048,
+            "B": 3072,
+            "L": 4096,
+            "So400m": 4304,
+            "H": 5120,
+            "g": 6144,
+            "g-opt": 6144,
+            "G": 8192,
+            "G-opt": 8192,
+            "e": 15360,
+        }[v],
+        "num_heads": {
+            "mu": 2,
+            "Ti": 3,
+            "S": 6,
+            "M": 8,
+            "B": 12,
+            "L": 16,
+            "So400m": 16,
+            "H": 16,
+            "g": 16,
+            "g-opt": 16,
+            "G": 16,
+            "G-opt": 16,
+            "e": 16,
+        }[v],
+        # pylint:enable=line-too-long
+        **patch,
+    }
diff --git a/openpi_runtime/openpi/models/tokenizer.py b/openpi_runtime/openpi/models/tokenizer.py
new file mode 100644
index 0000000000000000000000000000000000000000..8a4966d6298619e52c7ba53359ccbbb8ba0b8cf6
--- /dev/null
+++ b/openpi_runtime/openpi/models/tokenizer.py
@@ -0,0 +1,371 @@
+import logging
+import os
+
+import jax
+import numpy as np
+import orbax.checkpoint as ocp
+import sentencepiece
+from transformers import AutoProcessor
+
+import openpi.models.utils.fsq_tokenizer as fsq_tokenizer
+import openpi.shared.download as download
+
+
+class PaligemmaTokenizer:
+    def __init__(self, max_len: int = 48):
+        self._max_len = max_len
+
+        path = download.maybe_download("gs://big_vision/paligemma_tokenizer.model", gs={"token": "anon"})
+        with path.open("rb") as f:
+            self._tokenizer = sentencepiece.SentencePieceProcessor(model_proto=f.read())
+
+    def tokenize(self, prompt: str, state: np.ndarray | None = None) -> tuple[np.ndarray, np.ndarray]:
+        cleaned_text = prompt.strip().replace("_", " ").replace("\n", " ")
+        if state is not None:
+            # This is the Pi05 format, where the state is part of the discrete language input.
+            discretized_state = np.digitize(state, bins=np.linspace(-1, 1, 256 + 1)[:-1]) - 1
+            state_str = " ".join(map(str, discretized_state))
+            full_prompt = f"Task: {cleaned_text}, State: {state_str};\nAction: "
+            tokens = self._tokenizer.encode(full_prompt, add_bos=True)
+        else:
+            # This is the Pi0 format, where the state is part of the continuous action expert input.
+            # tokenize "\n" separately as the "start of answer" token
+            tokens = self._tokenizer.encode(cleaned_text, add_bos=True) + self._tokenizer.encode("\n")
+        tokens_len = len(tokens)
+        if tokens_len < self._max_len:
+            padding = [False] * (self._max_len - tokens_len)
+            mask = [True] * tokens_len + padding
+            tokens = tokens + padding
+        else:
+            if len(tokens) > self._max_len:
+                logging.warning(
+                    f"Token length ({len(tokens)}) exceeds max length ({self._max_len}), truncating. "
+                    "Consider increasing the `max_token_len` in your model config if this happens frequently."
+                )
+            tokens = tokens[: self._max_len]
+            mask = [True] * self._max_len
+
+        return np.asarray(tokens), np.asarray(mask)
+
+
+class FASTTokenizer:
+    def __init__(self, max_len: int = 256, fast_tokenizer_path: str = "physical-intelligence/fast"):
+        self._max_len = max_len
+
+        # Download base PaliGemma tokenizer
+        path = download.maybe_download("gs://big_vision/paligemma_tokenizer.model", gs={"token": "anon"})
+        with path.open("rb") as f:
+            self._paligemma_tokenizer = sentencepiece.SentencePieceProcessor(model_proto=f.read())
+
+        # Instantiate FAST tokenizer
+        self._fast_tokenizer = AutoProcessor.from_pretrained(fast_tokenizer_path, trust_remote_code=True)
+        self._fast_skip_tokens = 128  # Skip last 128 tokens in PaliGemma vocab since they are special tokens
+
+    def tokenize(
+        self, prompt: str, state: np.ndarray, actions: np.ndarray | None
+    ) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
+        cleaned_text = prompt.lower().strip().replace("_", " ")
+
+        # Convention: state gets discretized into 256 discrete bins (assumed range after normalization: [-1, 1])
+        discretized_state = np.digitize(state, bins=np.linspace(-1, 1, 256 + 1)[:-1]) - 1
+
+        # Convention: prefix includes prompt and string-representation of state, followed by ';'
+        state_str = " ".join(map(str, discretized_state))
+        prefix = f"Task: {cleaned_text}, State: {state_str};\n"
+        prefix_tokens = self._paligemma_tokenizer.encode(prefix, add_bos=True)
+
+        if actions is not None:
+            # Tokenize actions with FAST tokenizer --> map to last tokens in PaliGemma vocab
+            action_tokens = self._fast_tokenizer(actions[None])[0]
+            action_tokens_in_pg = self._act_tokens_to_paligemma_tokens(action_tokens)
+
+            # Convention: postfix contains 'Action:' followed by FAST tokens, followed by '|'
+            postfix_tokens = (
+                self._paligemma_tokenizer.encode("Action: ")
+                + action_tokens_in_pg.tolist()
+                + self._paligemma_tokenizer.encode("|", add_eos=True)
+            )
+        else:
+            postfix_tokens = []
+
+        # Create output token sequence & masks
+        # AR mask is 0 on prefix (bidirectional attention) and 1 on postfix (causal attention to all previous tokens)
+        tokens = prefix_tokens + postfix_tokens
+        token_mask = [True] * len(tokens)
+        ar_mask = [0] * len(prefix_tokens) + [1] * len(postfix_tokens)
+        loss_mask = [False] * len(prefix_tokens) + [True] * len(postfix_tokens)  # Loss on postfix only
+
+        # Pad tokens to max length
+        tokens_len = len(tokens)
+        if tokens_len < self._max_len:
+            padding = [False] * (self._max_len - tokens_len)
+            tokens = tokens + padding
+            token_mask = token_mask + padding
+            ar_mask = ar_mask + padding
+            loss_mask = loss_mask + padding
+        else:
+            if len(tokens) > self._max_len:
+                logging.warning(
+                    f"Token length ({len(tokens)}) exceeds max length ({self._max_len}), truncating. "
+                    "Consider increasing the `max_token_len` in your model config if this happens frequently."
+                )
+            tokens = tokens[: self._max_len]
+            token_mask = token_mask[: self._max_len]
+            ar_mask = ar_mask[: self._max_len]
+            loss_mask = loss_mask[: self._max_len]
+
+        return np.asarray(tokens), np.asarray(token_mask), np.asarray(ar_mask), np.asarray(loss_mask)
+
+    def extract_actions(self, tokens: np.ndarray, action_horizon: int, action_dim: int) -> np.ndarray:
+        # Decode predicted output tokens
+        decoded_tokens = self._paligemma_tokenizer.decode(tokens.tolist())
+
+        # Extract actions from FAST model outputs
+        if "Action: " not in decoded_tokens:
+            return np.zeros((action_horizon, action_dim), dtype=np.float32)
+
+        # Extract actions from decoded tokens
+        raw_action_tokens = np.array(
+            self._paligemma_tokenizer.encode(decoded_tokens.split("Action: ")[1].split("|")[0].strip())
+        )
+        action_tokens = self._act_tokens_to_paligemma_tokens(raw_action_tokens)
+        return self._fast_tokenizer.decode(
+            [action_tokens.tolist()], time_horizon=action_horizon, action_dim=action_dim
+        )[0]
+
+    def _act_tokens_to_paligemma_tokens(self, tokens: np.ndarray | list[int]) -> np.ndarray:
+        if isinstance(tokens, list):
+            tokens = np.array(tokens)
+        return self._paligemma_tokenizer.vocab_size() - 1 - self._fast_skip_tokens - tokens
+
+
+###########################################################################
+## The tokenizers below are used for RoboArena baseline implementations. ##
+## They are *not* used for pi0-style models.                             ##
+###########################################################################
+
+
+class BinningTokenizer:
+    """
+    Standard RT-2 / OpenVLA style binning tokenizer.
+    """
+
+    def __init__(self, max_len: int = 256, n_bins: int = 256):
+        self._max_len = max_len
+        self._n_bins = n_bins
+
+        # Download base PaliGemma tokenizer
+        path = download.maybe_download("gs://big_vision/paligemma_tokenizer.model", gs={"token": "anon"})
+        with path.open("rb") as f:
+            self._paligemma_tokenizer = sentencepiece.SentencePieceProcessor(model_proto=f.read())
+
+        self._fast_skip_tokens = 128  # Skip last 128 tokens in PaliGemma vocab since they are special tokens
+
+    def tokenize(
+        self, prompt: str, state: np.ndarray, actions: np.ndarray | None
+    ) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
+        """Tokenize a prompt and state into a sequence of tokens.
+
+        Args:
+            prompt: The text prompt to tokenize.
+            state: The state array to discretize and tokenize.
+            actions: Must be None. Action encoding is not currently supported.
+
+        Returns:
+            A tuple of (tokens, token_mask, ar_mask, targets).
+
+        Raises:
+            NotImplementedError: If actions is not None.
+        """
+        cleaned_text = prompt.lower().strip().replace("_", " ")
+
+        # Convention: state gets discretized into 256 discrete bins (assumed range after normalization: [-1, 1])
+        discretized_state = np.digitize(state, bins=np.linspace(-1, 1, 256 + 1)[:-1]) - 1
+
+        # Convention: prefix includes prompt and string-representation of state, followed by ';'
+        state_str = " ".join(map(str, discretized_state))
+        prefix = f"Task: {cleaned_text}, State: {state_str};\n"
+        prefix_tokens = self._paligemma_tokenizer.encode(prefix, add_bos=True)
+
+        if actions is not None:
+            raise NotImplementedError("BinningTokenizer does not support encoding actions atm (only for inference use)")
+        postfix_tokens = []
+
+        # Create output token sequence & masks
+        # AR mask is 0 on prefix (bidirectional attention) and 1 on postfix (causal attention to all previous tokens)
+        tokens = prefix_tokens + postfix_tokens
+        token_mask = [True] * len(tokens)
+        ar_mask = [0] * len(prefix_tokens) + [1] * len(postfix_tokens)
+        loss_mask = [False] * len(prefix_tokens) + [True] * len(postfix_tokens)  # Loss on postfix only
+
+        # Pad tokens to max length
+        tokens_len = len(tokens)
+        if tokens_len < self._max_len:
+            padding = [False] * (self._max_len - tokens_len)
+            tokens = tokens + padding
+            token_mask = token_mask + padding
+            ar_mask = ar_mask + padding
+            loss_mask = loss_mask + padding
+        else:
+            if len(tokens) > self._max_len:
+                logging.warning(
+                    f"Token length ({len(tokens)}) exceeds max length ({self._max_len}), truncating. "
+                    "Consider increasing the `max_token_len` in your model config if this happens frequently."
+                )
+            tokens = tokens[: self._max_len]
+            token_mask = token_mask[: self._max_len]
+            ar_mask = ar_mask[: self._max_len]
+            loss_mask = loss_mask[: self._max_len]
+
+        return np.asarray(tokens), np.asarray(token_mask), np.asarray(ar_mask), np.asarray(loss_mask)
+
+    def extract_actions(self, tokens: np.ndarray, action_horizon: int, action_dim: int) -> np.ndarray:
+        # Decode predicted output tokens
+        decoded_tokens = self._paligemma_tokenizer.decode(tokens.tolist())
+
+        # Extract actions from FAST model outputs
+        if "Action: " not in decoded_tokens:
+            return np.zeros((action_horizon, action_dim), dtype=np.float32)
+
+        # Extract actions from decoded tokens
+        raw_action_tokens = np.array(
+            self._paligemma_tokenizer.encode(decoded_tokens.split("Action: ")[1].split("|")[0].strip())
+        )
+        action_tokens = self._act_tokens_to_paligemma_tokens(raw_action_tokens)
+        if len(action_tokens) < action_horizon * action_dim:
+            return np.zeros([action_horizon, action_dim], dtype=np.float32)
+        action_tokens = action_tokens[: (action_horizon * action_dim)].reshape([action_horizon, action_dim])
+        return action_tokens / self._n_bins * 2 - 1
+
+    def _act_tokens_to_paligemma_tokens(self, tokens: np.ndarray | list[int]) -> np.ndarray:
+        if isinstance(tokens, list):
+            tokens = np.array(tokens)
+        return self._paligemma_tokenizer.vocab_size() - 1 - self._fast_skip_tokens - tokens
+
+
+class FSQTokenizer:
+    """
+    FSQ tokenizer from the FAST paper baselines.
+    """
+
+    def __init__(self, max_len: int = 256, fsq_tokenizer_path: str | None = None):
+        self._max_len = max_len
+
+        assert fsq_tokenizer_path is not None, "fsq_tokenizer_path must be provided"
+        # Download tokenizer
+        path = download.maybe_download(fsq_tokenizer_path)
+        tok_path = os.path.join(path, os.listdir(path)[0])
+
+        # Split step from path
+        step = int(tok_path.split("/")[-1])
+        base_path = tok_path.rsplit("/", 1)[0]
+
+        mgr = ocp.CheckpointManager(
+            base_path,
+            item_handlers={
+                "params": ocp.StandardCheckpointHandler(),
+                "opt_state": ocp.StandardCheckpointHandler(),
+                "config": ocp.JsonCheckpointHandler(),
+            },
+            options=ocp.CheckpointManagerOptions(max_to_keep=1),
+        )
+
+        try:
+            restored = mgr.restore(
+                step, args=ocp.args.Composite(config=ocp.args.JsonRestore(), params=ocp.args.StandardRestore())
+            )
+            config = restored["config"]
+            self._params = restored["params"]
+            self._fsq_tokenizer = fsq_tokenizer.FsqAttentionTokenizer(**config)
+        except Exception as e:
+            raise RuntimeError(
+                f"Failed to load FSQ tokenizer checkpoint from {fsq_tokenizer_path}. Error: {e!s}"
+            ) from e
+
+        # Compile tokenize and detokenize functions
+        self._tokenize_fn = jax.jit(
+            lambda params, x: self._fsq_tokenizer.apply({"params": params}, x, method=self._fsq_tokenizer.tokenize)
+        )
+        self._detokenize_fn = jax.jit(
+            lambda params, x: self._fsq_tokenizer.apply({"params": params}, x, method=self._fsq_tokenizer.detokenize)
+        )
+
+        # Download base PaliGemma tokenizer
+        path = download.maybe_download("gs://big_vision/paligemma_tokenizer.model", gs={"token": "anon"})
+        with path.open("rb") as f:
+            self._paligemma_tokenizer = sentencepiece.SentencePieceProcessor(model_proto=f.read())
+
+        self._fast_skip_tokens = 128  # Skip last 128 tokens in PaliGemma vocab since they are special tokens
+
+    def tokenize(
+        self, prompt: str, state: np.ndarray, actions: np.ndarray | None
+    ) -> tuple[np.ndarray, np.ndarray, np.ndarray, np.ndarray]:
+        cleaned_text = prompt.lower().strip().replace("_", " ")
+
+        # Convention: state gets discretized into 256 discrete bins (assumed range after normalization: [-1, 1])
+        discretized_state = np.digitize(state, bins=np.linspace(-1, 1, 256 + 1)[:-1]) - 1
+
+        # Convention: prefix includes prompt and string-representation of state, followed by ';'
+        state_str = " ".join(map(str, discretized_state))
+        prefix = f"Task: {cleaned_text}, State: {state_str};\n"
+        prefix_tokens = self._paligemma_tokenizer.encode(prefix, add_bos=True)
+
+        if actions is not None:
+            raise NotImplementedError("FSQTokenizer does not support encoding actions atm (only for inference use)")
+        postfix_tokens = []
+
+        # Create output token sequence & masks
+        # AR mask is 0 on prefix (bidirectional attention) and 1 on postfix (causal attention to all previous tokens)
+        tokens = prefix_tokens + postfix_tokens
+        token_mask = [True] * len(tokens)
+        ar_mask = [0] * len(prefix_tokens) + [1] * len(postfix_tokens)
+        loss_mask = [False] * len(prefix_tokens) + [True] * len(postfix_tokens)  # Loss on postfix only
+
+        # Pad tokens to max length
+        tokens_len = len(tokens)
+        if tokens_len < self._max_len:
+            padding = [False] * (self._max_len - tokens_len)
+            tokens = tokens + padding
+            token_mask = token_mask + padding
+            ar_mask = ar_mask + padding
+            loss_mask = loss_mask + padding
+        else:
+            if len(tokens) > self._max_len:
+                logging.warning(
+                    f"Token length ({len(tokens)}) exceeds max length ({self._max_len}), truncating. "
+                    "Consider increasing the `max_token_len` in your model config if this happens frequently."
+                )
+            tokens = tokens[: self._max_len]
+            token_mask = token_mask[: self._max_len]
+            ar_mask = ar_mask[: self._max_len]
+            loss_mask = loss_mask[: self._max_len]
+
+        return np.asarray(tokens), np.asarray(token_mask), np.asarray(ar_mask), np.asarray(loss_mask)
+
+    def extract_actions(self, tokens: np.ndarray, action_horizon: int, action_dim: int) -> np.ndarray:
+        # Decode predicted output tokens
+        decoded_tokens = self._paligemma_tokenizer.decode(tokens.tolist())
+
+        # Extract actions from FAST model outputs
+        if "Action: " not in decoded_tokens:
+            return np.zeros((action_horizon, action_dim), dtype=np.float32)
+
+        # Extract actions from decoded tokens
+        raw_action_tokens = np.array(
+            self._paligemma_tokenizer.encode(decoded_tokens.split("Action: ")[1].split("|")[0].strip())
+        )
+        action_tokens = self._act_tokens_to_paligemma_tokens(raw_action_tokens)
+        try:
+            # Move computation to CPU and compile on-demand
+            device = jax.devices("cpu")[0]
+            with jax.default_device(device):
+                detok_act = self._detokenize_fn(self._params, action_tokens[None, ...])[0]
+            return detok_act[: action_horizon * action_dim].reshape([action_horizon, action_dim])
+        except Exception as e:
+            logging.warning(f"Error decoding FSQ: {e}")
+            return np.zeros((action_horizon, action_dim))
+
+    def _act_tokens_to_paligemma_tokens(self, tokens: np.ndarray | list[int]) -> np.ndarray:
+        if isinstance(tokens, list):
+            tokens = np.array(tokens)
+        return self._paligemma_tokenizer.vocab_size() - 1 - self._fast_skip_tokens - tokens
diff --git a/openpi_runtime/openpi/models/utils/fsq_tokenizer.py b/openpi_runtime/openpi/models/utils/fsq_tokenizer.py
new file mode 100644
index 0000000000000000000000000000000000000000..574d7733de0ebd25898d8f82fdc6e37bd0aa75ab
--- /dev/null
+++ b/openpi_runtime/openpi/models/utils/fsq_tokenizer.py
@@ -0,0 +1,472 @@
+import math
+from typing import Any, Literal
+
+import chex
+from einops import einops
+from flax import linen as nn
+from flax.linen.module import Module
+from flax.linen.module import compact
+from flax.struct import dataclass
+from flax.typing import Array
+import jax
+import jax.numpy as jnp
+
+
+class FsqCodebook(nn.Module):
+    input_dim: int
+    target_codebook_size: int
+    codebook_type: Literal["fsq", "lfq"]
+
+    _bins_per_dim: tuple[int] | None = None
+
+    @property
+    def bins_per_dim(self) -> tuple[int]:
+        if self._bins_per_dim is not None:
+            return self._bins_per_dim
+
+        if self.codebook_type == "fsq":
+            return self._get_bins_fsq(self.target_codebook_size)
+        elif self.codebook_type == "lfq":  # noqa: RET505
+            return self._get_bins_lfq(self.target_codebook_size)
+        elif self.codebook_type == "custom":
+            return self._get_bins_custom(self.target_codebook_size)
+        else:
+            raise ValueError(f"Codebook type {self.codebook_type} not supported.")
+
+    @property
+    def place_values(self) -> jnp.ndarray:
+        place_values = [1]
+        for b in self.bins_per_dim[:-1]:
+            place_values.append(place_values[-1] * b)
+        return jnp.array(place_values)
+
+    @staticmethod
+    def _get_bins_fsq(target_codebook_size: int) -> tuple[int]:
+        """
+        Get bins per dimension based on codebook size, from the original FSQ paper.
+        """
+        if target_codebook_size == 2**8:
+            return (8, 6, 5)
+        elif target_codebook_size == 2**10:  # noqa: RET505
+            return (8, 5, 5, 5)
+        elif target_codebook_size == 2**12:
+            return (7, 5, 5, 5, 5)
+        elif target_codebook_size == 2**14:
+            return (8, 8, 8, 6, 5)
+        elif target_codebook_size == 2**16:
+            return (8, 8, 8, 5, 5, 5)
+        else:
+            raise ValueError(f"Codebook size {target_codebook_size} not supported.")
+
+    @staticmethod
+    def _get_bins_custom(target_codebook_size: int) -> tuple[int]:
+        if target_codebook_size == 2**8:
+            return (16, 16)
+        elif target_codebook_size == 2**10:  # noqa: RET505
+            return (32, 32)
+        elif target_codebook_size == 2**12:
+            return (64, 64)
+        elif target_codebook_size == 2**14:
+            return (128, 128)
+        elif target_codebook_size == 2**16:
+            return (256, 256)
+        return None
+
+    @staticmethod
+    def _get_bins_lfq(target_codebook_size: int) -> tuple[int]:
+        """
+        Get bins per dimension according to the Lookup-Free Quantization paper (2 bins per dimension)
+        """
+        assert target_codebook_size & (target_codebook_size - 1) == 0, "Codebook size should be a power of two for LFQ"
+
+        return (2,) * int(math.log2(target_codebook_size))
+
+    def setup(self):
+        self.proj_down = nn.Dense(len(self.bins_per_dim))
+        self.proj_up = nn.Dense(self.input_dim)
+
+    def __call__(self, inputs: jnp.ndarray) -> tuple[jnp.ndarray, jnp.ndarray]:
+        tokens, z = self.encode(inputs)
+        output = self.decode(tokens, z_grad=z)
+        return tokens, output
+
+    def encode(self, inputs: jnp.ndarray) -> tuple[jnp.ndarray, jnp.ndarray]:
+        bases = jnp.array(self.bins_per_dim)
+
+        x = self.proj_down(inputs)
+        z = jnp.tanh(x)
+
+        # Quantize
+        digits = jnp.round((z + 1) * (bases - 1) / 2).astype(jnp.int32)
+        tokens = self.undigitize(digits)
+
+        return tokens, z
+
+    def decode(self, tokens: jnp.ndarray, z_grad: jax.Array | None = None) -> jnp.ndarray:
+        bases = jnp.array(self.bins_per_dim)
+        digits = self.digitize(tokens)
+
+        z_q = digits / (bases - 1) * 2 - 1
+
+        if z_grad is not None:
+            chex.assert_equal_shape([z_q, z_grad])
+            z_q = jax.lax.stop_gradient(z_q - z_grad) + z_grad
+
+        return self.proj_up(z_q)
+
+    def undigitize(self, digits: jnp.ndarray) -> jnp.ndarray:
+        return jnp.sum(digits * jnp.array(self.place_values), axis=-1)
+
+    def digitize(self, tokens: jnp.ndarray) -> jnp.ndarray:
+        return (tokens[..., None] // jnp.array(self.place_values)) % jnp.array(self.bins_per_dim)
+
+    @property
+    def vocab_size(self) -> int:
+        return math.prod(self.bins_per_dim)
+
+
+class ResNetDownBlock(nn.Module):
+    stride: int = 1
+    n_filters: int = 64
+    dropout_rate: float = 0.0
+    group_size: int = 32
+
+    @nn.compact
+    def __call__(self, x: jnp.ndarray, *, train: bool = True) -> jnp.ndarray:
+        skip = x
+
+        if self.stride > 1 or x.shape[-1] != self.n_filters:
+            skip = nn.Conv(self.n_filters, (self.stride,), (self.stride,), "SAME")(skip)
+
+        x = nn.Conv(self.n_filters, (3,), (self.stride,), "SAME")(x)
+        x = nn.GroupNorm(num_groups=self.n_filters // self.group_size)(x)
+        x = nn.Dropout(self.dropout_rate)(x, deterministic=not train)
+        x = nn.relu(x)
+        x = nn.Conv(self.n_filters, (3,), (1,), "SAME")(x)
+
+        return skip + x
+
+
+class ResNetUpBlock(nn.Module):
+    stride: int = 1
+    n_filters: int = 64
+    dropout_rate: float = 0.0
+    group_size: int = 32
+
+    @nn.compact
+    def __call__(self, x: jnp.ndarray, *, train: bool = True) -> jnp.ndarray:
+        skip = x
+
+        if self.stride > 1:
+            skip = nn.ConvTranspose(self.n_filters, (self.stride,), (self.stride,), "SAME")(skip)
+
+        x = nn.ConvTranspose(self.n_filters, (3,), (self.stride,), "SAME")(x)
+        x = nn.GroupNorm(num_groups=self.n_filters // self.group_size)(x)
+        x = nn.Dropout(self.dropout_rate)(x, deterministic=not train)
+        x = nn.relu(x)
+        x = nn.ConvTranspose(self.n_filters, (3,), (1,), "SAME")(x)
+
+        return skip + x
+
+
+@dataclass
+class LfqCodebookOutput:
+    tokens: jnp.ndarray
+    z: jnp.ndarray
+    z_q: jnp.ndarray
+    token_log_probs: jnp.ndarray
+    commit_loss: jnp.ndarray
+
+
+class LookupFreeQuantization(nn.Module):
+    num_dims: int
+    latent_dim: int
+
+    def setup(self):
+        self.codebook = jnp.array([-1, 1])
+        self.activation = nn.tanh
+
+        self.project_down = nn.Dense(self.num_dims)
+        self.project_up = nn.Dense(self.latent_dim)
+
+    def encode(self, z: jnp.ndarray) -> jnp.ndarray:
+        z = self.project_down(z)
+        token_squared_distances = jnp.square(z[..., None] - self.codebook)
+        token_bits = jnp.argmin(token_squared_distances, axis=-1)
+        return jnp.sum(token_bits * (2 ** jnp.arange(self.num_dims)), axis=-1)
+
+    def decode(self, tokens: jnp.ndarray) -> jnp.ndarray:
+        token_bits = (tokens[..., None] & (2 ** jnp.arange(self.num_dims))).astype(jnp.int32)
+        return self.project_up(self.codebook[token_bits])
+
+    def loss(self, x: jnp.ndarray) -> LfqCodebookOutput:
+        z = self.project_down(x)
+        z = self.activation(z)
+
+        token_squared_distances = jnp.square(z[..., None] - self.codebook)
+        tokens = jnp.argmin(token_squared_distances, axis=-1)
+
+        token_bit_log_probs = -token_squared_distances
+        # Compute token log probs for tokens 0..2^num_dims-1 by summing corresponding log-probs
+        token_bit_expansions = jnp.bitwise_and(
+            jnp.arange(2**self.num_dims)[None, :], 2 ** jnp.arange(self.num_dims)[:, None]
+        ).astype(jnp.int32)
+        token_log_probs = (
+            token_bit_log_probs[..., 0] @ (1 - token_bit_expansions)
+            + token_bit_log_probs[..., 1] @ token_bit_expansions
+        )  # (batch_size, num_tokens, 2 ** num_dims)
+        token_log_probs = jax.lax.stop_gradient(jax.nn.log_softmax(token_log_probs, axis=-1))
+        chex.assert_shape(token_log_probs, (*x.shape[:-1], 2**self.num_dims))
+
+        z_q = self.codebook[tokens]
+        commit_loss = jnp.square(z - z_q).mean()
+        z_q = jax.lax.stop_gradient(z_q - z) + z
+
+        z_q = self.project_up(z_q)
+        z = self.project_up(z)
+
+        tokens = jnp.sum(tokens * (len(self.codebook) ** jnp.arange(self.num_dims)), axis=-1)
+        return LfqCodebookOutput(
+            tokens=tokens,
+            z=z,
+            z_q=z_q,
+            token_log_probs=jnp.zeros(()),
+            commit_loss=commit_loss,
+        )
+
+
+def make_block_causal_attention_matrix(q: jnp.ndarray, k: jnp.ndarray, bs_q: int, bs_k: int) -> jnp.ndarray:
+    return nn.make_attention_mask(q, k, pairwise_fn=lambda x, y: jnp.greater_equal(x // bs_k, y // bs_q))
+
+
+class GeGLU(Module):
+    """Gated Linear Unit with GELU (GeGLU) activation function.
+    GeGLU is a Flax layer that combines a linear transformation with a GELU
+    activation function in a gating mechanism. It is often used in Transformer models
+    to provide non-linear capabilities while preserving a strong linear component.
+
+    Attributes:
+        features: the number of output features (default: None).
+    """
+
+    output_dim: int = -1
+
+    @compact
+    def __call__(self, inputs: Array) -> Array:
+        """Applies the GeGLU activation to the inputs.
+        Args:
+            inputs: the nd-array to apply the GeGLU activation function to.
+        Returns:
+            The transformed input.
+        """
+        output_dim = inputs.shape[-1] if self.output_dim == -1 else self.output_dim
+
+        x = nn.Dense(output_dim * 2)(inputs)
+        x, gate = x[..., :output_dim], x[..., output_dim:]
+        return x * nn.gelu(gate)
+
+
+class CrossAttentionLayer(nn.Module):
+    dropout_rate: float = 0.0
+    num_heads: int = None
+    causal: bool = False
+    mlp_ratio: float = 4.0
+
+    @nn.compact
+    def __call__(
+        self,
+        x: jnp.ndarray,
+        y: jnp.ndarray,
+        *,
+        mask_self: jnp.ndarray | None = None,
+        mask_cross: jnp.ndarray | None = None,
+        train: bool = True,
+    ) -> jnp.ndarray:
+        d_embed = x.shape[-1]
+        seq_len_q = x.shape[-2]
+        seq_len_k = y.shape[-2]
+
+        if self.causal:
+            # One block size will be 1
+            bs_q = max(seq_len_q // seq_len_k, 1)
+            bs_k = max(seq_len_k // seq_len_q, 1)
+
+            mask_self = nn.make_causal_mask(x[..., 0])
+            mask_cross = make_block_causal_attention_matrix(x[..., 0], y[..., 0], bs_q, bs_k)
+
+        # Self-attention block
+        skip = x
+        x = nn.LayerNorm()(x)
+        x = nn.MultiHeadDotProductAttention(
+            num_heads=self.num_heads or d_embed // 64,
+            dropout_rate=self.dropout_rate,
+            deterministic=not train,
+        )(x, x, x, mask=mask_self)
+        x = skip + x
+
+        # Cross-attention block
+        skip = x
+        x = nn.LayerNorm()(x)
+        x = nn.MultiHeadDotProductAttention(
+            num_heads=self.num_heads or d_embed // 64,
+            dropout_rate=self.dropout_rate,
+            deterministic=not train,
+        )(x, y, y, mask=mask_cross)
+        x = skip + x
+
+        # MLP block
+        skip = x
+        x = nn.LayerNorm()(x)
+        x = nn.Dense(int(d_embed * self.mlp_ratio))(x)
+        x = nn.Dropout(self.dropout_rate)(x, deterministic=not train)
+        x = GeGLU()(x)
+        x = nn.Dense(d_embed)(x)
+        return skip + x
+
+
+def sinusoidal_pe_init(_, shape: tuple[int, int]) -> jnp.ndarray:
+    seq_len, d_embed = shape
+
+    position = jnp.arange(0, seq_len, 1)
+    div_term = jnp.exp(jnp.arange(0, d_embed, 2) * -(jnp.log(10000.0) / d_embed))
+    return jnp.concatenate(
+        [
+            jnp.sin(position[:, jnp.newaxis] * div_term),
+            jnp.cos(position[:, jnp.newaxis] * div_term),
+        ],
+        axis=-1,
+    )
+
+
+class TokenizerEncoderDecoder(nn.Module):
+    num_tokens: int
+    num_cross_tokens: int
+    num_layers: int
+    causal: bool
+
+    mlp_ratio: float = 4.0
+    use_state_conditioning: bool = False
+
+    @nn.compact
+    def __call__(
+        self,
+        y: jnp.ndarray,
+        *,
+        train: bool = True,
+        state_conditioning: jnp.ndarray | None = None,
+        mask: jnp.ndarray | None = None,
+    ) -> jnp.ndarray:
+        x = self.param("q_embed", sinusoidal_pe_init, (self.num_tokens, y.shape[-1]))
+        x = jax.numpy.broadcast_to(x, y.shape[:-2] + x.shape[-2:])
+
+        if mask is not None:
+            # mask is (batch_dims..., num_cross_tokens)
+            chex.assert_equal_shape([y[..., 0], mask])
+            attn_mask = einops.repeat(mask, "... kv -> ... 1 q kv", q=self.num_tokens)
+        else:
+            attn_mask = jnp.ones((*y.shape[:-2], 1, self.num_tokens, self.num_cross_tokens))
+
+        if self.use_state_conditioning:
+            assert state_conditioning is not None, "State conditioning is required for this model."
+            state_embed = nn.Dense(y.shape[-1], name="state_proj")(state_conditioning)[..., None, :]
+            y = jnp.concatenate([y, state_embed], axis=-2)
+            attn_mask = jnp.concatenate([attn_mask, jnp.ones_like(attn_mask[..., 0:1])], axis=-1)
+
+        y = y + self.param("y_pos_enc", sinusoidal_pe_init, y.shape[-2:])
+
+        for _ in range(self.num_layers):
+            x = CrossAttentionLayer(causal=self.causal, mlp_ratio=self.mlp_ratio)(
+                x, y, train=train, mask_self=None, mask_cross=attn_mask
+            )
+
+        return x
+
+
+class FsqAttentionTokenizer(nn.Module):
+    embed_dim: int
+    data_dim: int
+    data_horizon: int
+    num_tokens: int
+    num_layers: int
+    target_codebook_size: int
+    causal: bool = False
+    mlp_ratio: float = 2.0
+
+    bound: float | None = None
+
+    use_state_conditioning: bool = False
+
+    @property
+    def vocab_size(self) -> int:
+        return math.prod(FsqCodebook._get_bins_fsq(self.target_codebook_size))  # noqa: SLF001
+
+    def setup(self):
+        self.proj = nn.Dense(self.embed_dim)
+        self.encoder = TokenizerEncoderDecoder(
+            num_tokens=self.num_tokens,
+            num_cross_tokens=self.data_horizon,
+            num_layers=self.num_layers,
+            causal=self.causal,
+            use_state_conditioning=self.use_state_conditioning,
+            mlp_ratio=self.mlp_ratio,
+        )
+        self.codebook = FsqCodebook(
+            input_dim=self.embed_dim,
+            target_codebook_size=self.target_codebook_size,
+            codebook_type="custom",
+        )
+        self.decoder = TokenizerEncoderDecoder(
+            num_tokens=self.data_horizon,
+            num_cross_tokens=self.num_tokens,
+            num_layers=self.num_layers,
+            causal=self.causal,
+            use_state_conditioning=self.use_state_conditioning,
+            mlp_ratio=self.mlp_ratio,
+        )
+
+        self.proj_mean = nn.Dense(self.data_dim)
+        self.out_scale = self.param("out_scale", lambda _: jnp.full((), 1.0))
+
+    def tokenize(
+        self, action: jnp.ndarray, *, obs: jnp.ndarray | None = None, train: bool = False
+    ) -> tuple[jnp.ndarray, jnp.ndarray]:
+        if self.bound is not None:
+            action = jnp.clip(action, -self.bound, self.bound)
+
+        x = self.proj(action)
+        x = self.encoder(x, train=train, state_conditioning=obs)
+
+        return self.codebook.encode(x)
+
+    def detokenize(self, tokens: jnp.ndarray, *, obs: jnp.ndarray | None = None) -> jnp.ndarray:
+        x = self.decoder(self.codebook.decode(tokens), state_conditioning=obs)
+        mean = self.proj_mean(x)
+        return mean * self.out_scale
+
+    def loss(
+        self, action: jnp.ndarray, *, obs: jnp.ndarray | None = None, train: bool = True
+    ) -> tuple[jnp.ndarray, dict[str, jnp.ndarray]]:
+        # Encode
+        x = self.proj(action)
+        z = self.encoder(x, train=train, state_conditioning=obs)
+
+        # Quantize
+        tokens, z = self.codebook(z)
+
+        # Decode
+        x = self.decoder(z, train=train, state_conditioning=obs)
+        mean = self.proj_mean(x) * self.out_scale
+
+        mse = jnp.mean(jnp.square(action - mean))
+        mae = jnp.mean(jnp.abs(action - mean))
+
+        return mse, {
+            "mse": mse,
+            "mae": mae,
+        }
+
+    def __call__(self, *args: Any, **kwargs: Any) -> tuple[jnp.ndarray, dict[str, jnp.ndarray]]:
+        """
+        Dummy for .init
+        """
+        return self.loss(*args, **kwargs)
diff --git a/openpi_runtime/openpi/models/vit.py b/openpi_runtime/openpi/models/vit.py
new file mode 100644
index 0000000000000000000000000000000000000000..b7901d097b86d36e3564d2b664ed50af8a194080
--- /dev/null
+++ b/openpi_runtime/openpi/models/vit.py
@@ -0,0 +1,307 @@
+# Copyright 2024 Google LLC.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""ViT implementation adapted from https://github.com/google-research/vision_transformer/blob/main/vit_jax/models_vit.py."""
+
+from collections.abc import Callable
+from typing import Any
+
+import flax.linen as nn
+import jax
+import jax.numpy as jnp
+
+from openpi.models import resnet as models_resnet
+
+Array = Any
+PRNGKey = Any
+Shape = tuple[int]
+Dtype = Any
+
+
+class IdentityLayer(nn.Module):
+    """Identity layer, convenient for giving a name to an array."""
+
+    @nn.compact
+    def __call__(self, x):
+        return x
+
+
+class AddPositionEmbs(nn.Module):
+    """Adds learned positional embeddings to the inputs.
+
+    Attributes:
+      posemb_init: positional embedding initializer.
+    """
+
+    posemb_init: Callable[[PRNGKey, Shape, Dtype], Array]
+    param_dtype: Dtype = jnp.float32
+
+    @nn.compact
+    def __call__(self, inputs):
+        """Applies the AddPositionEmbs module.
+
+        Args:
+          inputs: Inputs to the layer.
+
+        Returns:
+          Output tensor with shape `(bs, timesteps, in_dim)`.
+        """
+        # inputs.shape is (batch_size, seq_len, emb_dim).
+        assert inputs.ndim == 3, f"Number of dimensions should be 3, but it is: {inputs.ndim}"
+        pos_emb_shape = (1, inputs.shape[1], inputs.shape[2])
+        pe = self.param("pos_embedding", self.posemb_init, pos_emb_shape, self.param_dtype)
+        return inputs + pe
+
+
+class MlpBlock(nn.Module):
+    """Transformer MLP / feed-forward block."""
+
+    mlp_dim: int
+    dtype: Dtype = jnp.float32
+    param_dtype: Dtype = jnp.float32
+    out_dim: int | None = None
+    dropout_rate: float = 0.1
+    kernel_init: Callable[[PRNGKey, Shape, Dtype], Array] = nn.initializers.xavier_uniform()
+    bias_init: Callable[[PRNGKey, Shape, Dtype], Array] = nn.initializers.normal(stddev=1e-6)
+
+    @nn.compact
+    def __call__(self, inputs, *, deterministic):
+        """Applies Transformer MlpBlock module."""
+        actual_out_dim = inputs.shape[-1] if self.out_dim is None else self.out_dim
+        x = nn.Dense(
+            features=self.mlp_dim,
+            dtype=self.dtype,
+            param_dtype=self.param_dtype,
+            kernel_init=self.kernel_init,
+            bias_init=self.bias_init,
+        )(  # pytype: disable=wrong-arg-types
+            inputs
+        )
+        x = nn.gelu(x)
+        x = nn.Dropout(rate=self.dropout_rate)(x, deterministic=deterministic)
+        output = nn.Dense(
+            features=actual_out_dim,
+            dtype=self.dtype,
+            param_dtype=self.param_dtype,
+            kernel_init=self.kernel_init,
+            bias_init=self.bias_init,
+        )(  # pytype: disable=wrong-arg-types
+            x
+        )
+        return nn.Dropout(rate=self.dropout_rate)(output, deterministic=deterministic)
+
+
+class Encoder1DBlock(nn.Module):
+    """Transformer encoder layer.
+
+    Attributes:
+      inputs: input data.
+      mlp_dim: dimension of the mlp on top of attention block.
+      dtype: the dtype of the computation (default: float32).
+      dropout_rate: dropout rate.
+      attention_dropout_rate: dropout for attention heads.
+      deterministic: bool, deterministic or not (to apply dropout).
+      num_heads: Number of heads in nn.MultiHeadDotProductAttention
+    """
+
+    mlp_dim: int
+    num_heads: int
+    dtype: Dtype = jnp.float32
+    dropout_rate: float = 0.1
+    attention_dropout_rate: float = 0.1
+
+    @nn.compact
+    def __call__(self, inputs, deterministic):
+        """Applies Encoder1DBlock module.
+
+        Args:
+          inputs: Inputs to the layer.
+          deterministic: Dropout will not be applied when set to true.
+
+        Returns:
+          output after transformer encoder block.
+        """
+
+        # Attention block.
+        assert inputs.ndim == 3, f"Expected (batch, seq, hidden) got {inputs.shape}"
+        x = nn.LayerNorm(dtype=self.dtype)(inputs)
+        x = nn.MultiHeadDotProductAttention(
+            dtype=self.dtype,
+            kernel_init=nn.initializers.xavier_uniform(),
+            broadcast_dropout=False,
+            deterministic=deterministic,
+            dropout_rate=self.attention_dropout_rate,
+            num_heads=self.num_heads,
+            # why isn't this true by default???
+            force_fp32_for_softmax=True,
+        )(x, x)
+        x = nn.Dropout(rate=self.dropout_rate)(x, deterministic=deterministic)
+        x = x + inputs
+
+        # MLP block.
+        y = nn.LayerNorm(dtype=self.dtype)(x)
+        y = MlpBlock(mlp_dim=self.mlp_dim, dtype=self.dtype, dropout_rate=self.dropout_rate)(
+            y, deterministic=deterministic
+        )
+
+        return x + y, None
+
+
+class Encoder(nn.Module):
+    """Transformer Model Encoder for sequence to sequence translation.
+
+    Attributes:
+      num_layers: number of layers
+      mlp_dim: dimension of the mlp on top of attention block
+      num_heads: Number of heads in nn.MultiHeadDotProductAttention
+      dropout_rate: dropout rate.
+      attention_dropout_rate: dropout rate in self attention.
+    """
+
+    dtype: jax.typing.DTypeLike
+    num_layers: int
+    mlp_dim: int
+    num_heads: int
+    dropout_rate: float = 0.1
+    attention_dropout_rate: float = 0.1
+    add_position_embedding: bool = True
+
+    @nn.compact
+    def __call__(self, x, *, train):
+        """Applies Transformer model on the inputs.
+
+        Args:
+          x: Inputs to the layer.
+          train: Set to `True` when training.
+
+        Returns:
+          output of a transformer encoder.
+        """
+        assert x.ndim == 3  # (batch, len, emb)
+
+        if self.add_position_embedding:
+            x = AddPositionEmbs(
+                posemb_init=nn.initializers.normal(stddev=0.02),  # from BERT.
+                name="posembed_input",
+            )(x)
+            x = nn.Dropout(rate=self.dropout_rate)(x, deterministic=not train)
+
+        x = x.astype(self.dtype)
+        # Input Encoder
+        block = nn.remat(Encoder1DBlock, prevent_cse=False, static_argnums=(2,))
+        x, _ = nn.scan(
+            block,
+            variable_axes={"params": 0},
+            split_rngs={"params": True, "dropout": True},
+            in_axes=nn.broadcast,
+            length=self.num_layers,
+        )(
+            name="encoderblock",
+            mlp_dim=self.mlp_dim,
+            dropout_rate=self.dropout_rate,
+            attention_dropout_rate=self.attention_dropout_rate,
+            dtype=self.dtype,
+            num_heads=self.num_heads,
+        )(x, not train)
+        return nn.LayerNorm(name="encoder_norm", dtype=self.dtype)(x)
+
+
+class VisionTransformer(nn.Module):
+    """VisionTransformer."""
+
+    dtype: jax.typing.DTypeLike
+    num_classes: int
+    patches: Any
+    transformer: Any
+    hidden_size: int
+    resnet: Any | None = None
+    representation_size: int | None = None
+    classifier: str = "token"
+    head_bias_init: float = 0.0
+    encoder: type[nn.Module] = Encoder
+    model_name: str | None = None
+
+    @nn.compact
+    def __call__(self, inputs, *, train):
+        x = inputs
+        # (Possibly partial) ResNet root.
+        if self.resnet is not None:
+            width = int(64 * self.resnet.width_factor)
+
+            # Root block.
+            x = models_resnet.StdConv(
+                features=width, kernel_size=(7, 7), strides=(2, 2), use_bias=False, name="conv_root"
+            )(x)
+            x = nn.GroupNorm(name="gn_root")(x)
+            x = nn.relu(x)
+            x = nn.max_pool(x, window_shape=(3, 3), strides=(2, 2), padding="SAME")
+
+            # ResNet stages.
+            if self.resnet.num_layers:
+                x = models_resnet.ResNetStage(
+                    block_size=self.resnet.num_layers[0], nout=width, first_stride=(1, 1), name="block1"
+                )(x)
+                for i, block_size in enumerate(self.resnet.num_layers[1:], 1):
+                    x = models_resnet.ResNetStage(
+                        block_size=block_size, nout=width * 2**i, first_stride=(2, 2), name=f"block{i + 1}"
+                    )(x)
+
+        n, h, w, c = x.shape
+
+        # We can merge s2d+emb into a single conv; it's the same.
+        x = nn.Conv(
+            features=self.hidden_size,
+            kernel_size=self.patches.size,
+            strides=self.patches.size,
+            padding="VALID",
+            name="embedding",
+        )(x)
+
+        # Here, x is a grid of embeddings.
+
+        # (Possibly partial) Transformer.
+        if self.transformer is not None:
+            n, h, w, c = x.shape
+            x = jnp.reshape(x, [n, h * w, c])
+
+            # If we want to add a class token, add it here.
+            if self.classifier in ["token", "token_unpooled"]:
+                cls = self.param("cls", nn.initializers.zeros, (1, 1, c))
+                cls = jnp.tile(cls, [n, 1, 1])
+                x = jnp.concatenate([cls, x], axis=1)
+
+            x = self.encoder(name="Transformer", **self.transformer, dtype=self.dtype)(x, train=train)
+
+        if self.classifier == "token":
+            x = x[:, 0]
+        elif self.classifier == "gap":
+            x = jnp.mean(x, axis=list(range(1, x.ndim - 1)))  # (1,) or (1,2)
+        elif self.classifier in ["unpooled", "token_unpooled"]:
+            pass
+        else:
+            raise ValueError(f"Invalid classifier={self.classifier}")
+
+        if self.representation_size is not None:
+            x = nn.Dense(features=self.representation_size, name="pre_logits")(x)
+            x = nn.tanh(x)
+        else:
+            x = IdentityLayer(name="pre_logits")(x)
+
+        if self.num_classes:
+            x = nn.Dense(
+                features=self.num_classes,
+                name="head",
+                kernel_init=nn.initializers.zeros,
+                bias_init=nn.initializers.constant(self.head_bias_init),
+            )(x)
+        return x
diff --git a/openpi_runtime/openpi/models_pytorch/gemma_pytorch.py b/openpi_runtime/openpi/models_pytorch/gemma_pytorch.py
new file mode 100644
index 0000000000000000000000000000000000000000..ecc597a9a23ffb26db8c1907fd264c4af797d786
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/gemma_pytorch.py
@@ -0,0 +1,280 @@
+from typing import Literal
+
+import torch
+from torch import nn
+from transformers import GemmaForCausalLM
+from transformers import PaliGemmaForConditionalGeneration
+from transformers.models.auto import CONFIG_MAPPING
+from transformers.models.gemma import modeling_gemma
+
+
+class PaliGemmaWithExpertModel(nn.Module):
+    def __init__(
+        self,
+        vlm_config,
+        action_expert_config,
+        use_adarms=None,
+        precision: Literal["bfloat16", "float32"] = "bfloat16",
+    ):
+        if use_adarms is None:
+            use_adarms = [False, False]
+        super().__init__()
+
+        vlm_config_hf = CONFIG_MAPPING["paligemma"]()
+        vlm_config_hf._vocab_size = 257152  # noqa: SLF001
+        vlm_config_hf.image_token_index = 257152
+        vlm_config_hf.text_config.hidden_size = vlm_config.width
+        vlm_config_hf.text_config.intermediate_size = vlm_config.mlp_dim
+        vlm_config_hf.text_config.num_attention_heads = vlm_config.num_heads
+        vlm_config_hf.text_config.head_dim = vlm_config.head_dim
+        vlm_config_hf.text_config.num_hidden_layers = vlm_config.depth
+        vlm_config_hf.text_config.num_key_value_heads = vlm_config.num_kv_heads
+        vlm_config_hf.text_config.hidden_activation = "gelu_pytorch_tanh"
+        vlm_config_hf.text_config.torch_dtype = "float32"
+        vlm_config_hf.text_config.vocab_size = 257152
+        vlm_config_hf.text_config.use_adarms = use_adarms[0]
+        vlm_config_hf.text_config.adarms_cond_dim = vlm_config.width if use_adarms[0] else None
+        vlm_config_hf.vision_config.intermediate_size = 4304
+        vlm_config_hf.vision_config.projection_dim = 2048
+        vlm_config_hf.vision_config.projector_hidden_act = "gelu_fast"
+        vlm_config_hf.vision_config.torch_dtype = "float32"
+
+        action_expert_config_hf = CONFIG_MAPPING["gemma"](
+            head_dim=action_expert_config.head_dim,
+            hidden_size=action_expert_config.width,
+            intermediate_size=action_expert_config.mlp_dim,
+            num_attention_heads=action_expert_config.num_heads,
+            num_hidden_layers=action_expert_config.depth,
+            num_key_value_heads=action_expert_config.num_kv_heads,
+            vocab_size=257152,
+            hidden_activation="gelu_pytorch_tanh",
+            torch_dtype="float32",
+            use_adarms=use_adarms[1],
+            adarms_cond_dim=action_expert_config.width if use_adarms[1] else None,
+        )
+
+        self.paligemma = PaliGemmaForConditionalGeneration(config=vlm_config_hf)
+        self.gemma_expert = GemmaForCausalLM(config=action_expert_config_hf)
+        self.gemma_expert.model.embed_tokens = None
+
+        self.to_bfloat16_for_selected_params(precision)
+
+    def to_bfloat16_for_selected_params(self, precision: Literal["bfloat16", "float32"] = "bfloat16"):
+        if precision == "bfloat16":
+            self.to(dtype=torch.bfloat16)
+        elif precision == "float32":
+            self.to(dtype=torch.float32)
+            return
+        else:
+            raise ValueError(f"Invalid precision: {precision}")
+
+        params_to_keep_float32 = [
+            "vision_tower.vision_model.embeddings.patch_embedding.weight",
+            "vision_tower.vision_model.embeddings.patch_embedding.bias",
+            "vision_tower.vision_model.embeddings.position_embedding.weight",
+            "input_layernorm",
+            "post_attention_layernorm",
+            "model.norm",
+        ]
+
+        for name, param in self.named_parameters():
+            if any(selector in name for selector in params_to_keep_float32):
+                param.data = param.data.to(dtype=torch.float32)
+
+    def embed_image(self, image: torch.Tensor):
+        return self.paligemma.model.get_image_features(image)
+
+    def embed_language_tokens(self, tokens: torch.Tensor):
+        return self.paligemma.language_model.embed_tokens(tokens)
+
+    def forward(
+        self,
+        attention_mask: torch.Tensor | None = None,
+        position_ids: torch.LongTensor | None = None,
+        past_key_values: list[torch.FloatTensor] | None = None,
+        inputs_embeds: list[torch.FloatTensor] | None = None,
+        use_cache: bool | None = None,
+        adarms_cond: list[torch.Tensor] | None = None,
+    ):
+        if adarms_cond is None:
+            adarms_cond = [None, None]
+        if inputs_embeds[1] is None:
+            prefix_output = self.paligemma.language_model.forward(
+                inputs_embeds=inputs_embeds[0],
+                attention_mask=attention_mask,
+                position_ids=position_ids,
+                past_key_values=past_key_values,
+                use_cache=use_cache,
+                adarms_cond=adarms_cond[0] if adarms_cond is not None else None,
+            )
+            prefix_past_key_values = prefix_output.past_key_values
+            prefix_output = prefix_output.last_hidden_state
+            suffix_output = None
+        elif inputs_embeds[0] is None:
+            suffix_output = self.gemma_expert.model.forward(
+                inputs_embeds=inputs_embeds[1],
+                attention_mask=attention_mask,
+                position_ids=position_ids,
+                past_key_values=past_key_values,
+                use_cache=use_cache,
+                adarms_cond=adarms_cond[1] if adarms_cond is not None else None,
+            )
+            suffix_output = suffix_output.last_hidden_state
+            prefix_output = None
+            prefix_past_key_values = None
+        else:
+            models = [self.paligemma.language_model, self.gemma_expert.model]
+            num_layers = self.paligemma.config.text_config.num_hidden_layers
+
+            # Check if gradient checkpointing is enabled for any of the models
+            use_gradient_checkpointing = (
+                hasattr(self.gemma_expert.model, "gradient_checkpointing")
+                and self.gemma_expert.model.gradient_checkpointing
+                and self.training
+            ) or (hasattr(self, "gradient_checkpointing") and self.gradient_checkpointing and self.training)
+
+            # Force enable gradient checkpointing if we're in training mode and the model supports it
+            if self.training and hasattr(self.gemma_expert.model, "gradient_checkpointing"):
+                if not self.gemma_expert.model.gradient_checkpointing:
+                    print("Forcing gradient checkpointing to be enabled for Gemma expert model")
+                    self.gemma_expert.model.gradient_checkpointing = True
+                use_gradient_checkpointing = True
+
+            # Debug gradient checkpointing status
+            if hasattr(self, "_debug_gc_printed") and not self._debug_gc_printed:
+                print(f"Gemma expert model gradient checkpointing: {use_gradient_checkpointing}")
+                print(f"Model training mode: {self.training}")
+                print(
+                    f"Gemma expert model has gradient_checkpointing attr: {hasattr(self.gemma_expert.model, 'gradient_checkpointing')}"
+                )
+                if hasattr(self.gemma_expert.model, "gradient_checkpointing"):
+                    print(
+                        f"Gemma expert model gradient_checkpointing value: {self.gemma_expert.model.gradient_checkpointing}"
+                    )
+                self._debug_gc_printed = True
+
+            # Define the complete layer computation function for gradient checkpointing
+            def compute_layer_complete(layer_idx, inputs_embeds, attention_mask, position_ids, adarms_cond):
+                models = [self.paligemma.language_model, self.gemma_expert.model]
+
+                query_states = []
+                key_states = []
+                value_states = []
+                gates = []
+                for i, hidden_states in enumerate(inputs_embeds):
+                    layer = models[i].layers[layer_idx]
+                    hidden_states, gate = layer.input_layernorm(hidden_states, cond=adarms_cond[i])  # noqa: PLW2901
+                    gates.append(gate)
+
+                    input_shape = hidden_states.shape[:-1]
+                    hidden_shape = (*input_shape, -1, layer.self_attn.head_dim)
+                    query_state = layer.self_attn.q_proj(hidden_states).view(hidden_shape).transpose(1, 2)
+                    key_state = layer.self_attn.k_proj(hidden_states).view(hidden_shape).transpose(1, 2)
+                    value_state = layer.self_attn.v_proj(hidden_states).view(hidden_shape).transpose(1, 2)
+
+                    query_states.append(query_state)
+                    key_states.append(key_state)
+                    value_states.append(value_state)
+
+                # Concatenate and process attention
+                query_states = torch.cat(query_states, dim=2)
+                key_states = torch.cat(key_states, dim=2)
+                value_states = torch.cat(value_states, dim=2)
+
+                dummy_tensor = torch.zeros(
+                    query_states.shape[0],
+                    query_states.shape[2],
+                    query_states.shape[-1],
+                    device=query_states.device,
+                    dtype=query_states.dtype,
+                )
+                cos, sin = self.paligemma.model.language_model.rotary_emb(dummy_tensor, position_ids)
+                query_states, key_states = modeling_gemma.apply_rotary_pos_emb(
+                    query_states, key_states, cos, sin, unsqueeze_dim=1
+                )
+
+                batch_size = query_states.shape[0]
+                scaling = self.paligemma.language_model.layers[layer_idx].self_attn.scaling
+
+                # Attention computation
+                att_output, _ = modeling_gemma.eager_attention_forward(
+                    self.paligemma.language_model.layers[layer_idx].self_attn,
+                    query_states,
+                    key_states,
+                    value_states,
+                    attention_mask,
+                    scaling,
+                )
+                # Get head_dim from the current layer, not from the model
+                head_dim = self.paligemma.language_model.layers[layer_idx].self_attn.head_dim
+                att_output = att_output.reshape(batch_size, -1, 1 * 8 * head_dim)
+
+                # Process layer outputs
+                outputs_embeds = []
+                start_pos = 0
+                for i, hidden_states in enumerate(inputs_embeds):
+                    layer = models[i].layers[layer_idx]
+                    end_pos = start_pos + hidden_states.shape[1]
+
+                    if att_output.dtype != layer.self_attn.o_proj.weight.dtype:
+                        att_output = att_output.to(layer.self_attn.o_proj.weight.dtype)
+                    out_emb = layer.self_attn.o_proj(att_output[:, start_pos:end_pos])
+
+                    # first residual
+                    out_emb = modeling_gemma._gated_residual(hidden_states, out_emb, gates[i])  # noqa: SLF001
+                    after_first_residual = out_emb.clone()
+                    out_emb, gate = layer.post_attention_layernorm(out_emb, cond=adarms_cond[i])
+                    # Convert to bfloat16 if the next layer (mlp) uses bfloat16
+                    if layer.mlp.up_proj.weight.dtype == torch.bfloat16:
+                        out_emb = out_emb.to(dtype=torch.bfloat16)
+
+                    out_emb = layer.mlp(out_emb)
+                    # second residual
+                    out_emb = modeling_gemma._gated_residual(after_first_residual, out_emb, gate)  # noqa: SLF001
+                    outputs_embeds.append(out_emb)
+                    start_pos = end_pos
+
+                return outputs_embeds
+
+            # Process all layers with gradient checkpointing if enabled
+            for layer_idx in range(num_layers):
+                if use_gradient_checkpointing:
+                    inputs_embeds = torch.utils.checkpoint.checkpoint(
+                        compute_layer_complete,
+                        layer_idx,
+                        inputs_embeds,
+                        attention_mask,
+                        position_ids,
+                        adarms_cond,
+                        use_reentrant=False,
+                        preserve_rng_state=False,
+                    )
+                else:
+                    inputs_embeds = compute_layer_complete(
+                        layer_idx, inputs_embeds, attention_mask, position_ids, adarms_cond
+                    )
+
+                # Old code removed - now using compute_layer_complete function above
+
+            # final norm
+            # Define final norm computation function for gradient checkpointing
+            def compute_final_norms(inputs_embeds, adarms_cond):
+                outputs_embeds = []
+                for i, hidden_states in enumerate(inputs_embeds):
+                    out_emb, _ = models[i].norm(hidden_states, cond=adarms_cond[i])
+                    outputs_embeds.append(out_emb)
+                return outputs_embeds
+
+            # Apply gradient checkpointing to final norm if enabled
+            if use_gradient_checkpointing:
+                outputs_embeds = torch.utils.checkpoint.checkpoint(
+                    compute_final_norms, inputs_embeds, adarms_cond, use_reentrant=False, preserve_rng_state=False
+                )
+            else:
+                outputs_embeds = compute_final_norms(inputs_embeds, adarms_cond)
+
+            prefix_output = outputs_embeds[0]
+            suffix_output = outputs_embeds[1]
+            prefix_past_key_values = None
+
+        return [prefix_output, suffix_output], prefix_past_key_values
diff --git a/openpi_runtime/openpi/models_pytorch/pi0_pytorch.py b/openpi_runtime/openpi/models_pytorch/pi0_pytorch.py
new file mode 100644
index 0000000000000000000000000000000000000000..e68ddb7cc02c2fd256e9b48ac9d0fb9df966536a
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/pi0_pytorch.py
@@ -0,0 +1,462 @@
+import logging
+import math
+
+import torch
+from torch import Tensor
+from torch import nn
+import torch.nn.functional as F  # noqa: N812
+
+import openpi.models.gemma as _gemma
+from openpi.models_pytorch.gemma_pytorch import PaliGemmaWithExpertModel
+import openpi.models_pytorch.preprocessing_pytorch as _preprocessing
+
+
+def get_safe_dtype(target_dtype, device_type):
+    """Get a safe dtype for the given device type."""
+    if device_type == "cpu":
+        # CPU doesn't support bfloat16, use float32 instead
+        if target_dtype == torch.bfloat16:
+            return torch.float32
+        if target_dtype == torch.float64:
+            return torch.float64
+    return target_dtype
+
+
+def create_sinusoidal_pos_embedding(
+    time: torch.tensor, dimension: int, min_period: float, max_period: float, device="cpu"
+) -> Tensor:
+    """Computes sine-cosine positional embedding vectors for scalar positions."""
+    if dimension % 2 != 0:
+        raise ValueError(f"dimension ({dimension}) must be divisible by 2")
+
+    if time.ndim != 1:
+        raise ValueError("The time tensor is expected to be of shape `(batch_size, )`.")
+
+    dtype = get_safe_dtype(torch.float64, device.type)
+    fraction = torch.linspace(0.0, 1.0, dimension // 2, dtype=dtype, device=device)
+    period = min_period * (max_period / min_period) ** fraction
+
+    # Compute the outer product
+    scaling_factor = 1.0 / period * 2 * math.pi
+    sin_input = scaling_factor[None, :] * time[:, None]
+    return torch.cat([torch.sin(sin_input), torch.cos(sin_input)], dim=1)
+
+
+def sample_beta(alpha, beta, bsize, device):
+    alpha_t = torch.as_tensor(alpha, dtype=torch.float32, device=device)
+    beta_t = torch.as_tensor(beta, dtype=torch.float32, device=device)
+    dist = torch.distributions.Beta(alpha_t, beta_t)
+    return dist.sample((bsize,))
+
+
+def make_att_2d_masks(pad_masks, att_masks):
+    """Copied from big_vision.
+
+    Tokens can attend to valid inputs tokens which have a cumulative mask_ar
+    smaller or equal to theirs. This way `mask_ar` int[B, N] can be used to
+    setup several types of attention, for example:
+
+      [[1 1 1 1 1 1]]: pure causal attention.
+
+      [[0 0 0 1 1 1]]: prefix-lm attention. The first 3 tokens can attend between
+          themselves and the last 3 tokens have a causal attention. The first
+          entry could also be a 1 without changing behaviour.
+
+      [[1 0 1 0 1 0 0 1 0 0]]: causal attention between 4 blocks. Tokens of a
+          block can attend all previous blocks and all tokens on the same block.
+
+    Args:
+      input_mask: bool[B, N] true if its part of the input, false if padding.
+      mask_ar: int32[B, N] mask that's 1 where previous tokens cannot depend on
+        it and 0 where it shares the same attention mask as the previous token.
+    """
+    if att_masks.ndim != 2:
+        raise ValueError(att_masks.ndim)
+    if pad_masks.ndim != 2:
+        raise ValueError(pad_masks.ndim)
+
+    cumsum = torch.cumsum(att_masks, dim=1)
+    att_2d_masks = cumsum[:, None, :] <= cumsum[:, :, None]
+    pad_2d_masks = pad_masks[:, None, :] * pad_masks[:, :, None]
+    return att_2d_masks & pad_2d_masks
+
+
+class PI0Pytorch(nn.Module):
+    def __init__(self, config):
+        super().__init__()
+        self.config = config
+        self.pi05 = config.pi05
+
+        paligemma_config = _gemma.get_config(config.paligemma_variant)
+        action_expert_config = _gemma.get_config(config.action_expert_variant)
+
+        self.paligemma_with_expert = PaliGemmaWithExpertModel(
+            paligemma_config,
+            action_expert_config,
+            use_adarms=[False, True] if self.pi05 else [False, False],
+            precision=config.dtype,
+        )
+
+        self.action_in_proj = nn.Linear(config.action_dim, action_expert_config.width)
+        self.action_out_proj = nn.Linear(action_expert_config.width, config.action_dim)
+
+        if self.pi05:
+            self.time_mlp_in = nn.Linear(action_expert_config.width, action_expert_config.width)
+            self.time_mlp_out = nn.Linear(action_expert_config.width, action_expert_config.width)
+        else:
+            self.state_proj = nn.Linear(config.action_dim, action_expert_config.width)
+            self.action_time_mlp_in = nn.Linear(2 * action_expert_config.width, action_expert_config.width)
+            self.action_time_mlp_out = nn.Linear(action_expert_config.width, action_expert_config.width)
+
+        torch.set_float32_matmul_precision("high")
+        if config.pytorch_compile_mode is not None:
+            self.sample_actions = torch.compile(self.sample_actions, mode=config.pytorch_compile_mode)
+
+        # Initialize gradient checkpointing flag
+        self.gradient_checkpointing_enabled = False
+
+        msg = "transformers_replace is not installed correctly. Please install it with `uv pip install transformers==4.53.2` and `cp -r ./src/openpi/models_pytorch/transformers_replace/* .venv/lib/python3.11/site-packages/transformers/`."
+        try:
+            from transformers.models.siglip import check
+
+            if not check.check_whether_transformers_replace_is_installed_correctly():
+                raise ValueError(msg)
+        except ImportError:
+            raise ValueError(msg) from None
+
+    def gradient_checkpointing_enable(self):
+        """Enable gradient checkpointing for memory optimization."""
+        self.gradient_checkpointing_enabled = True
+        self.paligemma_with_expert.paligemma.language_model.gradient_checkpointing = True
+        self.paligemma_with_expert.paligemma.vision_tower.gradient_checkpointing = True
+        self.paligemma_with_expert.gemma_expert.model.gradient_checkpointing = True
+
+        logging.info("Enabled gradient checkpointing for PI0Pytorch model")
+
+    def gradient_checkpointing_disable(self):
+        """Disable gradient checkpointing."""
+        self.gradient_checkpointing_enabled = False
+        self.paligemma_with_expert.paligemma.language_model.gradient_checkpointing = False
+        self.paligemma_with_expert.paligemma.vision_tower.gradient_checkpointing = False
+        self.paligemma_with_expert.gemma_expert.model.gradient_checkpointing = False
+
+        logging.info("Disabled gradient checkpointing for PI0Pytorch model")
+
+    def is_gradient_checkpointing_enabled(self):
+        """Check if gradient checkpointing is enabled."""
+        return self.gradient_checkpointing_enabled
+
+    def _apply_checkpoint(self, func, *args, **kwargs):
+        """Helper method to apply gradient checkpointing if enabled."""
+        if self.gradient_checkpointing_enabled and self.training:
+            return torch.utils.checkpoint.checkpoint(
+                func, *args, use_reentrant=False, preserve_rng_state=False, **kwargs
+            )
+        return func(*args, **kwargs)
+
+    def _prepare_attention_masks_4d(self, att_2d_masks):
+        """Helper method to prepare 4D attention masks for transformer."""
+        att_2d_masks_4d = att_2d_masks[:, None, :, :]
+        return torch.where(att_2d_masks_4d, 0.0, -2.3819763e38)
+
+    def _preprocess_observation(self, observation, *, train=True):
+        """Helper method to preprocess observation."""
+        observation = _preprocessing.preprocess_observation_pytorch(observation, train=train)
+        return (
+            list(observation.images.values()),
+            list(observation.image_masks.values()),
+            observation.tokenized_prompt,
+            observation.tokenized_prompt_mask,
+            observation.state,
+        )
+
+    def sample_noise(self, shape, device):
+        return torch.normal(
+            mean=0.0,
+            std=1.0,
+            size=shape,
+            dtype=torch.float32,
+            device=device,
+        )
+
+    def sample_time(self, bsize, device):
+        time_beta = sample_beta(1.5, 1.0, bsize, device)
+        time = time_beta * 0.999 + 0.001
+        return time.to(dtype=torch.float32, device=device)
+
+    def embed_prefix(
+        self, images, img_masks, lang_tokens, lang_masks
+    ) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
+        """Embed images with SigLIP and language tokens with embedding layer to prepare
+        for PaliGemma transformer processing.
+        """
+        embs = []
+        pad_masks = []
+        att_masks = []
+
+        # Process images
+        for img, img_mask in zip(images, img_masks, strict=True):
+
+            def image_embed_func(img):
+                return self.paligemma_with_expert.embed_image(img)
+
+            img_emb = self._apply_checkpoint(image_embed_func, img)
+
+            bsize, num_img_embs = img_emb.shape[:2]
+
+            embs.append(img_emb)
+            pad_masks.append(img_mask[:, None].expand(bsize, num_img_embs))
+
+            # Create attention masks so that image tokens attend to each other
+            att_masks += [0] * num_img_embs
+
+        # Process language tokens
+        def lang_embed_func(lang_tokens):
+            lang_emb = self.paligemma_with_expert.embed_language_tokens(lang_tokens)
+            lang_emb_dim = lang_emb.shape[-1]
+            return lang_emb * math.sqrt(lang_emb_dim)
+
+        lang_emb = self._apply_checkpoint(lang_embed_func, lang_tokens)
+
+        embs.append(lang_emb)
+        pad_masks.append(lang_masks)
+
+        # full attention between image and language inputs
+        num_lang_embs = lang_emb.shape[1]
+        att_masks += [0] * num_lang_embs
+
+        embs = torch.cat(embs, dim=1)
+        pad_masks = torch.cat(pad_masks, dim=1)
+        att_masks = torch.tensor(att_masks, dtype=torch.bool, device=pad_masks.device)
+
+        # Get batch size from the first dimension of the concatenated tensors
+        bsize = pad_masks.shape[0]
+        att_masks = att_masks[None, :].expand(bsize, len(att_masks))
+
+        return embs, pad_masks, att_masks
+
+    def embed_suffix(self, state, noisy_actions, timestep):
+        """Embed state, noisy_actions, timestep to prepare for Expert Gemma processing."""
+        embs = []
+        pad_masks = []
+        att_masks = []
+
+        if not self.pi05:
+            if self.state_proj.weight.dtype == torch.float32:
+                state = state.to(torch.float32)
+
+            # Embed state
+            def state_proj_func(state):
+                return self.state_proj(state)
+
+            state_emb = self._apply_checkpoint(state_proj_func, state)
+
+            embs.append(state_emb[:, None, :])
+            bsize = state_emb.shape[0]
+            device = state_emb.device
+
+            state_mask = torch.ones(bsize, 1, dtype=torch.bool, device=device)
+            pad_masks.append(state_mask)
+
+            # Set attention masks so that image and language inputs do not attend to state or actions
+            att_masks += [1]
+
+        # Embed timestep using sine-cosine positional encoding with sensitivity in the range [0, 1]
+        time_emb = create_sinusoidal_pos_embedding(
+            timestep, self.action_in_proj.out_features, min_period=4e-3, max_period=4.0, device=timestep.device
+        )
+        time_emb = time_emb.type(dtype=timestep.dtype)
+
+        # Fuse timestep + action information using an MLP
+        def action_proj_func(noisy_actions):
+            return self.action_in_proj(noisy_actions)
+
+        action_emb = self._apply_checkpoint(action_proj_func, noisy_actions)
+
+        if not self.pi05:
+            time_emb = time_emb[:, None, :].expand_as(action_emb)
+            action_time_emb = torch.cat([action_emb, time_emb], dim=2)
+
+            # Apply MLP layers
+            def mlp_func(action_time_emb):
+                x = self.action_time_mlp_in(action_time_emb)
+                x = F.silu(x)  # swish == silu
+                return self.action_time_mlp_out(x)
+
+            action_time_emb = self._apply_checkpoint(mlp_func, action_time_emb)
+            adarms_cond = None
+        else:
+            # time MLP (for adaRMS)
+            def time_mlp_func(time_emb):
+                x = self.time_mlp_in(time_emb)
+                x = F.silu(x)  # swish == silu
+                x = self.time_mlp_out(x)
+                return F.silu(x)
+
+            time_emb = self._apply_checkpoint(time_mlp_func, time_emb)
+            action_time_emb = action_emb
+            adarms_cond = time_emb
+
+        # Add to input tokens
+        embs.append(action_time_emb)
+
+        bsize, action_time_dim = action_time_emb.shape[:2]
+        action_time_mask = torch.ones(bsize, action_time_dim, dtype=torch.bool, device=timestep.device)
+        pad_masks.append(action_time_mask)
+
+        # Set attention masks so that image, language and state inputs do not attend to action tokens
+        att_masks += [1] + ([0] * (self.config.action_horizon - 1))
+
+        embs = torch.cat(embs, dim=1)
+        pad_masks = torch.cat(pad_masks, dim=1)
+        att_masks = torch.tensor(att_masks, dtype=embs.dtype, device=embs.device)
+        att_masks = att_masks[None, :].expand(bsize, len(att_masks))
+
+        return embs, pad_masks, att_masks, adarms_cond
+
+    def forward(self, observation, actions, noise=None, time=None) -> Tensor:
+        """Do a full training forward pass and compute the loss (batch_size x num_steps x num_motors)"""
+        images, img_masks, lang_tokens, lang_masks, state = self._preprocess_observation(observation, train=True)
+
+        if noise is None:
+            noise = self.sample_noise(actions.shape, actions.device)
+
+        if time is None:
+            time = self.sample_time(actions.shape[0], actions.device)
+
+        time_expanded = time[:, None, None]
+        x_t = time_expanded * noise + (1 - time_expanded) * actions
+        u_t = noise - actions
+
+        prefix_embs, prefix_pad_masks, prefix_att_masks = self.embed_prefix(images, img_masks, lang_tokens, lang_masks)
+        suffix_embs, suffix_pad_masks, suffix_att_masks, adarms_cond = self.embed_suffix(state, x_t, time)
+        if (
+            self.paligemma_with_expert.paligemma.language_model.layers[0].self_attn.q_proj.weight.dtype
+            == torch.bfloat16
+        ):
+            suffix_embs = suffix_embs.to(dtype=torch.bfloat16)
+            prefix_embs = prefix_embs.to(dtype=torch.bfloat16)
+
+        pad_masks = torch.cat([prefix_pad_masks, suffix_pad_masks], dim=1)
+        att_masks = torch.cat([prefix_att_masks, suffix_att_masks], dim=1)
+
+        att_2d_masks = make_att_2d_masks(pad_masks, att_masks)
+        position_ids = torch.cumsum(pad_masks, dim=1) - 1
+
+        # Prepare attention masks
+        att_2d_masks_4d = self._prepare_attention_masks_4d(att_2d_masks)
+
+        # Apply gradient checkpointing if enabled
+        def forward_func(prefix_embs, suffix_embs, att_2d_masks_4d, position_ids, adarms_cond):
+            (_, suffix_out), _ = self.paligemma_with_expert.forward(
+                attention_mask=att_2d_masks_4d,
+                position_ids=position_ids,
+                past_key_values=None,
+                inputs_embeds=[prefix_embs, suffix_embs],
+                use_cache=False,
+                adarms_cond=[None, adarms_cond],
+            )
+            return suffix_out
+
+        suffix_out = self._apply_checkpoint(
+            forward_func, prefix_embs, suffix_embs, att_2d_masks_4d, position_ids, adarms_cond
+        )
+
+        suffix_out = suffix_out[:, -self.config.action_horizon :]
+        suffix_out = suffix_out.to(dtype=torch.float32)
+
+        # Apply gradient checkpointing to final action projection if enabled
+        def action_out_proj_func(suffix_out):
+            return self.action_out_proj(suffix_out)
+
+        v_t = self._apply_checkpoint(action_out_proj_func, suffix_out)
+
+        return F.mse_loss(u_t, v_t, reduction="none")
+
+    @torch.no_grad()
+    def sample_actions(self, device, observation, noise=None, num_steps=10) -> Tensor:
+        """Do a full inference forward and compute the action (batch_size x num_steps x num_motors)"""
+        bsize = observation.state.shape[0]
+        if noise is None:
+            actions_shape = (bsize, self.config.action_horizon, self.config.action_dim)
+            noise = self.sample_noise(actions_shape, device)
+
+        images, img_masks, lang_tokens, lang_masks, state = self._preprocess_observation(observation, train=False)
+
+        prefix_embs, prefix_pad_masks, prefix_att_masks = self.embed_prefix(images, img_masks, lang_tokens, lang_masks)
+        prefix_att_2d_masks = make_att_2d_masks(prefix_pad_masks, prefix_att_masks)
+        prefix_position_ids = torch.cumsum(prefix_pad_masks, dim=1) - 1
+
+        # Compute image and language key value cache
+        prefix_att_2d_masks_4d = self._prepare_attention_masks_4d(prefix_att_2d_masks)
+        self.paligemma_with_expert.paligemma.language_model.config._attn_implementation = "eager"  # noqa: SLF001
+
+        _, past_key_values = self.paligemma_with_expert.forward(
+            attention_mask=prefix_att_2d_masks_4d,
+            position_ids=prefix_position_ids,
+            past_key_values=None,
+            inputs_embeds=[prefix_embs, None],
+            use_cache=True,
+        )
+
+        dt = -1.0 / num_steps
+        dt = torch.tensor(dt, dtype=torch.float32, device=device)
+
+        x_t = noise
+        time = torch.tensor(1.0, dtype=torch.float32, device=device)
+        while time >= -dt / 2:
+            expanded_time = time.expand(bsize)
+            v_t = self.denoise_step(
+                state,
+                prefix_pad_masks,
+                past_key_values,
+                x_t,
+                expanded_time,
+            )
+
+            # Euler step - use new tensor assignment instead of in-place operation
+            x_t = x_t + dt * v_t
+            time += dt
+        return x_t
+
+    def denoise_step(
+        self,
+        state,
+        prefix_pad_masks,
+        past_key_values,
+        x_t,
+        timestep,
+    ):
+        """Apply one denoising step of the noise `x_t` at a given timestep."""
+        suffix_embs, suffix_pad_masks, suffix_att_masks, adarms_cond = self.embed_suffix(state, x_t, timestep)
+
+        suffix_len = suffix_pad_masks.shape[1]
+        batch_size = prefix_pad_masks.shape[0]
+        prefix_len = prefix_pad_masks.shape[1]
+
+        prefix_pad_2d_masks = prefix_pad_masks[:, None, :].expand(batch_size, suffix_len, prefix_len)
+
+        suffix_att_2d_masks = make_att_2d_masks(suffix_pad_masks, suffix_att_masks)
+
+        full_att_2d_masks = torch.cat([prefix_pad_2d_masks, suffix_att_2d_masks], dim=2)
+
+        prefix_offsets = torch.sum(prefix_pad_masks, dim=-1)[:, None]
+        position_ids = prefix_offsets + torch.cumsum(suffix_pad_masks, dim=1) - 1
+
+        # Prepare attention masks
+        full_att_2d_masks_4d = self._prepare_attention_masks_4d(full_att_2d_masks)
+        self.paligemma_with_expert.gemma_expert.model.config._attn_implementation = "eager"  # noqa: SLF001
+
+        outputs_embeds, _ = self.paligemma_with_expert.forward(
+            attention_mask=full_att_2d_masks_4d,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=[None, suffix_embs],
+            use_cache=False,
+            adarms_cond=[None, adarms_cond],
+        )
+
+        suffix_out = outputs_embeds[1]
+        suffix_out = suffix_out[:, -self.config.action_horizon :]
+        suffix_out = suffix_out.to(dtype=torch.float32)
+        return self.action_out_proj(suffix_out)
diff --git a/openpi_runtime/openpi/models_pytorch/preprocessing_pytorch.py b/openpi_runtime/openpi/models_pytorch/preprocessing_pytorch.py
new file mode 100644
index 0000000000000000000000000000000000000000..33c94a59b18a7e45732a02200f0daef5b0f93018
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/preprocessing_pytorch.py
@@ -0,0 +1,173 @@
+from collections.abc import Sequence
+import logging
+
+import torch
+
+from openpi.shared import image_tools
+
+logger = logging.getLogger("openpi")
+
+# Constants moved from model.py
+IMAGE_KEYS = (
+    "base_0_rgb",
+    "left_wrist_0_rgb",
+    "right_wrist_0_rgb",
+)
+
+IMAGE_RESOLUTION = (224, 224)
+
+
+def preprocess_observation_pytorch(
+    observation,
+    *,
+    train: bool = False,
+    image_keys: Sequence[str] = IMAGE_KEYS,
+    image_resolution: tuple[int, int] = IMAGE_RESOLUTION,
+):
+    """Torch.compile-compatible version of preprocess_observation_pytorch with simplified type annotations.
+
+    This function avoids complex type annotations that can cause torch.compile issues.
+    """
+    if not set(image_keys).issubset(observation.images):
+        raise ValueError(f"images dict missing keys: expected {image_keys}, got {list(observation.images)}")
+
+    batch_shape = observation.state.shape[:-1]
+
+    out_images = {}
+    for key in image_keys:
+        image = observation.images[key]
+
+        # TODO: This is a hack to handle both [B, C, H, W] and [B, H, W, C] formats
+        # Handle both [B, C, H, W] and [B, H, W, C] formats
+        is_channels_first = image.shape[1] == 3  # Check if channels are in dimension 1
+
+        if is_channels_first:
+            # Convert [B, C, H, W] to [B, H, W, C] for processing
+            image = image.permute(0, 2, 3, 1)
+
+        if image.shape[1:3] != image_resolution:
+            logger.info(f"Resizing image {key} from {image.shape[1:3]} to {image_resolution}")
+            image = image_tools.resize_with_pad_torch(image, *image_resolution)
+
+        if train:
+            # Convert from [-1, 1] to [0, 1] for PyTorch augmentations
+            image = image / 2.0 + 0.5
+
+            # Apply PyTorch-based augmentations
+            if "wrist" not in key:
+                # Geometric augmentations for non-wrist cameras
+                height, width = image.shape[1:3]
+
+                # Random crop and resize
+                crop_height = int(height * 0.95)
+                crop_width = int(width * 0.95)
+
+                # Random crop
+                max_h = height - crop_height
+                max_w = width - crop_width
+                if max_h > 0 and max_w > 0:
+                    # Use tensor operations instead of .item() for torch.compile compatibility
+                    start_h = torch.randint(0, max_h + 1, (1,), device=image.device)
+                    start_w = torch.randint(0, max_w + 1, (1,), device=image.device)
+                    image = image[:, start_h : start_h + crop_height, start_w : start_w + crop_width, :]
+
+                # Resize back to original size
+                image = torch.nn.functional.interpolate(
+                    image.permute(0, 3, 1, 2),  # [b, h, w, c] -> [b, c, h, w]
+                    size=(height, width),
+                    mode="bilinear",
+                    align_corners=False,
+                ).permute(0, 2, 3, 1)  # [b, c, h, w] -> [b, h, w, c]
+
+                # Random rotation (small angles)
+                # Use tensor operations instead of .item() for torch.compile compatibility
+                angle = torch.rand(1, device=image.device) * 10 - 5  # Random angle between -5 and 5 degrees
+                if torch.abs(angle) > 0.1:  # Only rotate if angle is significant
+                    # Convert to radians
+                    angle_rad = angle * torch.pi / 180.0
+
+                    # Create rotation matrix
+                    cos_a = torch.cos(angle_rad)
+                    sin_a = torch.sin(angle_rad)
+
+                    # Apply rotation using grid_sample
+                    grid_x = torch.linspace(-1, 1, width, device=image.device)
+                    grid_y = torch.linspace(-1, 1, height, device=image.device)
+
+                    # Create meshgrid
+                    grid_y, grid_x = torch.meshgrid(grid_y, grid_x, indexing="ij")
+
+                    # Expand to batch dimension
+                    grid_x = grid_x.unsqueeze(0).expand(image.shape[0], -1, -1)
+                    grid_y = grid_y.unsqueeze(0).expand(image.shape[0], -1, -1)
+
+                    # Apply rotation transformation
+                    grid_x_rot = grid_x * cos_a - grid_y * sin_a
+                    grid_y_rot = grid_x * sin_a + grid_y * cos_a
+
+                    # Stack and reshape for grid_sample
+                    grid = torch.stack([grid_x_rot, grid_y_rot], dim=-1)
+
+                    image = torch.nn.functional.grid_sample(
+                        image.permute(0, 3, 1, 2),  # [b, h, w, c] -> [b, c, h, w]
+                        grid,
+                        mode="bilinear",
+                        padding_mode="zeros",
+                        align_corners=False,
+                    ).permute(0, 2, 3, 1)  # [b, c, h, w] -> [b, h, w, c]
+
+            # Color augmentations for all cameras
+            # Random brightness
+            # Use tensor operations instead of .item() for torch.compile compatibility
+            brightness_factor = 0.7 + torch.rand(1, device=image.device) * 0.6  # Random factor between 0.7 and 1.3
+            image = image * brightness_factor
+
+            # Random contrast
+            # Use tensor operations instead of .item() for torch.compile compatibility
+            contrast_factor = 0.6 + torch.rand(1, device=image.device) * 0.8  # Random factor between 0.6 and 1.4
+            mean = image.mean(dim=[1, 2, 3], keepdim=True)
+            image = (image - mean) * contrast_factor + mean
+
+            # Random saturation (convert to HSV, modify S, convert back)
+            # For simplicity, we'll just apply a random scaling to the color channels
+            # Use tensor operations instead of .item() for torch.compile compatibility
+            saturation_factor = 0.5 + torch.rand(1, device=image.device) * 1.0  # Random factor between 0.5 and 1.5
+            gray = image.mean(dim=-1, keepdim=True)
+            image = gray + (image - gray) * saturation_factor
+
+            # Clamp values to [0, 1]
+            image = torch.clamp(image, 0, 1)
+
+            # Back to [-1, 1]
+            image = image * 2.0 - 1.0
+
+        # Convert back to [B, C, H, W] format if it was originally channels-first
+        if is_channels_first:
+            image = image.permute(0, 3, 1, 2)  # [B, H, W, C] -> [B, C, H, W]
+
+        out_images[key] = image
+
+    # obtain mask
+    out_masks = {}
+    for key in out_images:
+        if key not in observation.image_masks:
+            # do not mask by default
+            out_masks[key] = torch.ones(batch_shape, dtype=torch.bool, device=observation.state.device)
+        else:
+            out_masks[key] = observation.image_masks[key]
+
+    # Create a simple object with the required attributes instead of using the complex Observation class
+    class SimpleProcessedObservation:
+        def __init__(self, **kwargs):
+            for key, value in kwargs.items():
+                setattr(self, key, value)
+
+    return SimpleProcessedObservation(
+        images=out_images,
+        image_masks=out_masks,
+        state=observation.state,
+        tokenized_prompt=observation.tokenized_prompt,
+        tokenized_prompt_mask=observation.tokenized_prompt_mask,
+        token_ar_mask=observation.token_ar_mask,
+        token_loss_mask=observation.token_loss_mask,
+    )
diff --git a/openpi_runtime/openpi/models_pytorch/transformers_replace/models/gemma/configuration_gemma.py b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/gemma/configuration_gemma.py
new file mode 100644
index 0000000000000000000000000000000000000000..a42abe1341d4cf30574cc5f239369cb5e55bfdbb
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/gemma/configuration_gemma.py
@@ -0,0 +1,173 @@
+#                🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
+#           This file was automatically generated from src/transformers/models/gemma/modular_gemma.py.
+#               Do NOT edit this file manually as any edits will be overwritten by the generation of
+#             the file from the modular. If any change should be done, please apply the change to the
+#                          modular_gemma.py file directly. One of our CI enforces this.
+#                🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
+# coding=utf-8
+# Copyright 2024 Google Inc. HuggingFace Inc. team. All rights reserved.
+#
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from typing import Optional
+from ...configuration_utils import PretrainedConfig
+
+
+class GemmaConfig(PretrainedConfig):
+    r"""
+    This is the configuration class to store the configuration of a [`GemmaModel`]. It is used to instantiate an Gemma
+    model according to the specified arguments, defining the model architecture. Instantiating a configuration with the
+    defaults will yield a similar configuration to that of the Gemma-7B.
+    e.g. [google/gemma-7b](https://huggingface.co/google/gemma-7b)
+    Configuration objects inherit from [`PretrainedConfig`] and can be used to control the model outputs. Read the
+    documentation from [`PretrainedConfig`] for more information.
+    Args:
+        vocab_size (`int`, *optional*, defaults to 256000):
+            Vocabulary size of the Gemma model. Defines the number of different tokens that can be represented by the
+            `inputs_ids` passed when calling [`GemmaModel`]
+        hidden_size (`int`, *optional*, defaults to 3072):
+            Dimension of the hidden representations.
+        intermediate_size (`int`, *optional*, defaults to 24576):
+            Dimension of the MLP representations.
+        num_hidden_layers (`int`, *optional*, defaults to 28):
+            Number of hidden layers in the Transformer decoder.
+        num_attention_heads (`int`, *optional*, defaults to 16):
+            Number of attention heads for each attention layer in the Transformer decoder.
+        num_key_value_heads (`int`, *optional*, defaults to 16):
+            This is the number of key_value heads that should be used to implement Grouped Query Attention. If
+            `num_key_value_heads=num_attention_heads`, the model will use Multi Head Attention (MHA), if
+            `num_key_value_heads=1` the model will use Multi Query Attention (MQA) otherwise GQA is used. When
+            converting a multi-head checkpoint to a GQA checkpoint, each group key and value head should be constructed
+            by meanpooling all the original heads within that group. For more details, check out [this
+            paper](https://huggingface.co/papers/2305.13245). If it is not specified, will default to
+            `num_attention_heads`.
+        head_dim (`int`, *optional*, defaults to 256):
+            The attention head dimension.
+        hidden_act (`str` or `function`, *optional*, defaults to `"gelu_pytorch_tanh"`):
+            The legacy activation function. It is overwritten by the `hidden_activation`.
+        hidden_activation (`str` or `function`, *optional*):
+            The non-linear activation function (function or string) in the decoder. Will default to `"gelu_pytorch_tanh"`
+            if not specified. `"gelu_pytorch_tanh"` uses an approximation of the `"gelu"` activation function.
+        max_position_embeddings (`int`, *optional*, defaults to 8192):
+            The maximum sequence length that this model might ever be used with.
+        initializer_range (`float`, *optional*, defaults to 0.02):
+            The standard deviation of the truncated_normal_initializer for initializing all weight matrices.
+        rms_norm_eps (`float`, *optional*, defaults to 1e-06):
+            The epsilon used by the rms normalization layers.
+        use_cache (`bool`, *optional*, defaults to `True`):
+            Whether or not the model should return the last key/values attentions (not used by all models). Only
+            relevant if `config.is_decoder=True`.
+        pad_token_id (`int`, *optional*, defaults to 0):
+            Padding token id.
+        eos_token_id (`int`, *optional*, defaults to 1):
+            End of stream token id.
+        bos_token_id (`int`, *optional*, defaults to 2):
+            Beginning of stream token id.
+        tie_word_embeddings (`bool`, *optional*, defaults to `True`):
+            Whether to tie weight embeddings
+        rope_theta (`float`, *optional*, defaults to 10000.0):
+            The base period of the RoPE embeddings.
+        attention_bias (`bool`, defaults to `False`, *optional*, defaults to `False`):
+            Whether to use a bias in the query, key, value and output projection layers during self-attention.
+        attention_dropout (`float`, *optional*, defaults to 0.0):
+            The dropout ratio for the attention probabilities.
+        use_adarms (`bool`, *optional*, defaults to `False`):
+            Whether to use ADARMS.
+        adarms_cond_dim (`int`, *optional*, defaults to `None`):
+            The dimension of the ADARMS condition.
+    ```python
+    >>> from transformers import GemmaModel, GemmaConfig
+    >>> # Initializing a Gemma gemma-7b style configuration
+    >>> configuration = GemmaConfig()
+    >>> # Initializing a model from the gemma-7b style configuration
+    >>> model = GemmaModel(configuration)
+    >>> # Accessing the model configuration
+    >>> configuration = model.config
+    ```"""
+
+    model_type = "gemma"
+    keys_to_ignore_at_inference = ["past_key_values"]
+    base_model_tp_plan = {
+        "layers.*.self_attn.q_proj": "colwise",
+        "layers.*.self_attn.k_proj": "colwise",
+        "layers.*.self_attn.v_proj": "colwise",
+        "layers.*.self_attn.o_proj": "rowwise",
+        "layers.*.mlp.gate_proj": "colwise",
+        "layers.*.mlp.up_proj": "colwise",
+        "layers.*.mlp.down_proj": "rowwise",
+    }
+    base_model_pp_plan = {
+        "embed_tokens": (["input_ids"], ["inputs_embeds"]),
+        "layers": (["hidden_states", "attention_mask"], ["hidden_states"]),
+        "norm": (["hidden_states"], ["hidden_states"]),
+    }
+
+    def __init__(
+        self,
+        vocab_size=256000,
+        hidden_size=3072,
+        intermediate_size=24576,
+        num_hidden_layers=28,
+        num_attention_heads=16,
+        num_key_value_heads=16,
+        head_dim=256,
+        hidden_act="gelu_pytorch_tanh",
+        hidden_activation=None,
+        max_position_embeddings=8192,
+        initializer_range=0.02,
+        rms_norm_eps=1e-6,
+        use_cache=True,
+        pad_token_id=0,
+        eos_token_id=1,
+        bos_token_id=2,
+        tie_word_embeddings=True,
+        rope_theta=10000.0,
+        attention_bias=False,
+        attention_dropout=0.0,
+        use_adarms: bool = False,
+        adarms_cond_dim: Optional[int] = None,
+        **kwargs,
+    ):
+        self.vocab_size = vocab_size
+        self.max_position_embeddings = max_position_embeddings
+        self.hidden_size = hidden_size
+        self.intermediate_size = intermediate_size
+        self.num_hidden_layers = num_hidden_layers
+        self.num_attention_heads = num_attention_heads
+        self.head_dim = head_dim
+        self.num_key_value_heads = num_key_value_heads
+        self.hidden_act = hidden_act
+        self.hidden_activation = hidden_activation
+        self.initializer_range = initializer_range
+        self.rms_norm_eps = rms_norm_eps
+        self.use_cache = use_cache
+        self.rope_theta = rope_theta
+        self.attention_bias = attention_bias
+        self.attention_dropout = attention_dropout
+        self.use_adarms = use_adarms
+        self.adarms_cond_dim = adarms_cond_dim
+
+        # Set default for adarms_cond_dim if use_adarms is True
+        if self.use_adarms and self.adarms_cond_dim is None:
+            self.adarms_cond_dim = self.hidden_size
+
+        super().__init__(
+            pad_token_id=pad_token_id,
+            bos_token_id=bos_token_id,
+            eos_token_id=eos_token_id,
+            tie_word_embeddings=tie_word_embeddings,
+            **kwargs,
+        )
+
+
+__all__ = ["GemmaConfig"]
\ No newline at end of file
diff --git a/openpi_runtime/openpi/models_pytorch/transformers_replace/models/gemma/modeling_gemma.py b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/gemma/modeling_gemma.py
new file mode 100644
index 0000000000000000000000000000000000000000..d0529778bba56e0a45279aa44e29ef9a379026d9
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/gemma/modeling_gemma.py
@@ -0,0 +1,862 @@
+#                🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
+#           This file was automatically generated from src/transformers/models/gemma/modular_gemma.py.
+#               Do NOT edit this file manually as any edits will be overwritten by the generation of
+#             the file from the modular. If any change should be done, please apply the change to the
+#                          modular_gemma.py file directly. One of our CI enforces this.
+#                🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
+# coding=utf-8
+# Copyright 2024 Google Inc. HuggingFace Inc. team. All rights reserved.
+#
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from typing import Callable, Optional, Union
+
+import torch
+from torch import nn
+
+from ...activations import ACT2FN
+from ...cache_utils import Cache, DynamicCache
+from ...generation import GenerationMixin
+from ...masking_utils import create_causal_mask
+from ...modeling_flash_attention_utils import FlashAttentionKwargs
+from ...modeling_layers import GradientCheckpointingLayer
+from ...modeling_outputs import (
+    BaseModelOutputWithPast,
+    CausalLMOutputWithPast,
+    SequenceClassifierOutputWithPast,
+    TokenClassifierOutput,
+)
+from ...modeling_rope_utils import ROPE_INIT_FUNCTIONS, dynamic_rope_update
+from ...modeling_utils import ALL_ATTENTION_FUNCTIONS, PreTrainedModel
+from ...processing_utils import Unpack
+from ...utils import LossKwargs, auto_docstring, can_return_tuple, logging
+from .configuration_gemma import GemmaConfig
+
+
+logger = logging.get_logger(__name__)
+
+
+class GemmaRMSNorm(nn.Module):
+    def __init__(self, dim: int, eps: float = 1e-6, cond_dim: Optional[int] = None):
+        super().__init__()
+        self.eps = eps
+        self.dim = dim
+        self.cond_dim = cond_dim
+        
+        # Dense layer for adaptive normalization (if cond_dim is provided)
+        if cond_dim is not None:
+            #self.dense = nn.Linear(cond_dim, dim * 3, bias=True, dtype=torch.bfloat16)
+            self.dense = nn.Linear(cond_dim, dim * 3, bias=True)
+            # Initialize with zeros (matches source implementation)
+            nn.init.zeros_(self.dense.weight)
+        else:
+            self.weight = nn.Parameter(torch.zeros(dim, dtype=torch.bfloat16))
+            self.dense = None
+
+    def _norm(self, x):
+        # Compute variance in float32 (like the source implementation)
+        var = torch.mean(torch.square(x.float()), dim=-1, keepdim=True)
+        # Compute normalization in float32
+        normed_inputs = x * torch.rsqrt(var + self.eps)
+        return normed_inputs
+
+    def forward(self, x, cond=None):
+        dtype = x.dtype  # original dtype, could be half-precision
+        normed_inputs = self._norm(x)
+        
+        if cond is None or self.dense is None:
+            # regular RMSNorm
+            # scale by learned parameter in float32 (matches source implementation)
+            normed_inputs = normed_inputs * (1.0 + self.weight.float())
+            return normed_inputs.to(dtype), None  # return in original dtype with None gate
+        
+        # adaptive RMSNorm (if cond is provided and dense layer exists)
+        if cond.shape[-1] != self.cond_dim:
+            raise ValueError(f"Expected cond dimension {self.cond_dim}, got {cond.shape[-1]}")
+        
+        #self.dense.to(dtype=torch.bfloat16).to(dtype=torch.float32)
+        modulation = self.dense(cond)
+        # Reshape modulation to broadcast properly: [batch, 1, features] for [batch, seq, features]
+        if len(x.shape) == 3:  # [batch, seq, features]
+            modulation = modulation.unsqueeze(1)
+        
+        scale, shift, gate = torch.chunk(modulation, 3, dim=-1)
+        
+        # Apply adaptive normalization: use model weight dtype to ensure compatibility
+        # model_dtype = self.dense.weight.dtype  # Use the model's dtype (bfloat16)
+        # scale = scale.to(model_dtype)
+        # shift = shift.to(model_dtype)
+        # gate = gate.to(model_dtype)
+        # normed_inputs = normed_inputs.to(model_dtype)  # Convert normed_inputs to model dtype
+        
+        normed_inputs = normed_inputs * (1 + scale.to(torch.float32)) + shift.to(torch.float32)
+
+        return normed_inputs.to(dtype), gate.to(dtype)
+
+    def extra_repr(self):
+        repr_str = f"{tuple(self.weight.shape)}, eps={self.eps}"
+        if self.dense is not None:
+            repr_str += f", adaptive=True, cond_dim={self.cond_dim}"
+        return repr_str
+
+
+class GemmaMLP(nn.Module):
+    def __init__(self, config):
+        super().__init__()
+        self.config = config
+        self.hidden_size = config.hidden_size
+        self.intermediate_size = config.intermediate_size
+        self.gate_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
+        self.up_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
+        self.down_proj = nn.Linear(self.intermediate_size, self.hidden_size, bias=False)
+        self.act_fn = ACT2FN[config.hidden_act]
+
+    def forward(self, x):
+        down_proj = self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x))
+        return down_proj
+
+
+class GemmaRotaryEmbedding(nn.Module):
+    def __init__(self, config: GemmaConfig, device=None):
+        super().__init__()
+        # BC: "rope_type" was originally "type"
+        if hasattr(config, "rope_scaling") and config.rope_scaling is not None:
+            self.rope_type = config.rope_scaling.get("rope_type", config.rope_scaling.get("type"))
+        else:
+            self.rope_type = "default"
+        self.max_seq_len_cached = config.max_position_embeddings
+        self.original_max_seq_len = config.max_position_embeddings
+
+        self.config = config
+        self.rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type]
+
+        inv_freq, self.attention_scaling = self.rope_init_fn(self.config, device)
+        self.register_buffer("inv_freq", inv_freq, persistent=False)
+        self.original_inv_freq = self.inv_freq
+
+    @torch.no_grad()
+    @dynamic_rope_update  # power user: used with advanced RoPE types (e.g. dynamic rope)
+    def forward(self, x, position_ids):
+        inv_freq_expanded = self.inv_freq[None, :, None].float().expand(position_ids.shape[0], -1, 1).to(x.device)
+        position_ids_expanded = position_ids[:, None, :].float()
+
+        device_type = x.device.type if isinstance(x.device.type, str) and x.device.type != "mps" else "cpu"
+        with torch.autocast(device_type=device_type, enabled=False):  # Force float32
+            freqs = (inv_freq_expanded.float() @ position_ids_expanded.float()).transpose(1, 2)
+            emb = torch.cat((freqs, freqs), dim=-1)
+            cos = emb.cos() * self.attention_scaling
+            sin = emb.sin() * self.attention_scaling
+
+        return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)
+
+
+def rotate_half(x):
+    """Rotates half the hidden dims of the input."""
+    x1 = x[..., : x.shape[-1] // 2]
+    x2 = x[..., x.shape[-1] // 2 :]
+    return torch.cat((-x2, x1), dim=-1)
+
+
+def apply_rotary_pos_emb(q, k, cos, sin, position_ids=None, unsqueeze_dim=1):
+    """Applies Rotary Position Embedding to the query and key tensors.
+
+    Args:
+        q (`torch.Tensor`): The query tensor.
+        k (`torch.Tensor`): The key tensor.
+        cos (`torch.Tensor`): The cosine part of the rotary embedding.
+        sin (`torch.Tensor`): The sine part of the rotary embedding.
+        position_ids (`torch.Tensor`, *optional*):
+            Deprecated and unused.
+        unsqueeze_dim (`int`, *optional*, defaults to 1):
+            The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
+            sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
+            that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
+            k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
+            cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
+            the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
+    Returns:
+        `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
+    """
+    cos = cos.unsqueeze(unsqueeze_dim)
+    sin = sin.unsqueeze(unsqueeze_dim)
+    q_embed = (q * cos) + (rotate_half(q) * sin)
+    k_embed = (k * cos) + (rotate_half(k) * sin)
+    return q_embed, k_embed
+
+
+def repeat_kv(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor:
+    """
+    This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch,
+    num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim)
+    """
+    batch, num_key_value_heads, slen, head_dim = hidden_states.shape
+    if n_rep == 1:
+        return hidden_states
+    hidden_states = hidden_states[:, :, None, :, :].expand(batch, num_key_value_heads, n_rep, slen, head_dim)
+    return hidden_states.reshape(batch, num_key_value_heads * n_rep, slen, head_dim)
+
+
+def _gated_residual(x, y, gate):
+    """
+    Applies gated residual connection with optional gate parameter.
+    
+    Args:
+        x: Input tensor (residual)
+        y: Output tensor to be added
+        gate: Optional gate tensor to modulate the addition
+        
+    Returns:
+        x + y if gate is None, otherwise x + y * gate
+    """
+    if x is None and y is None:
+        return None
+    if x is None or y is None:
+        return x if x is not None else y
+    if gate is None:
+        return x + y
+    return x + y * gate
+
+
+def eager_attention_forward(
+    module: nn.Module,
+    query: torch.Tensor,
+    key: torch.Tensor,
+    value: torch.Tensor,
+    attention_mask: Optional[torch.Tensor],
+    scaling: float,
+    dropout: float = 0.0,
+    **kwargs,
+):
+    key_states = repeat_kv(key, module.num_key_value_groups)
+    value_states = repeat_kv(value, module.num_key_value_groups)
+
+    attn_weights = torch.matmul(query, key_states.transpose(2, 3)) * scaling
+    if attention_mask is not None:
+        causal_mask = attention_mask[:, :, :, : key_states.shape[-2]]
+        attn_weights = attn_weights + causal_mask
+
+    attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(query.dtype)
+    attn_weights = nn.functional.dropout(attn_weights, p=dropout, training=module.training)
+    attn_output = torch.matmul(attn_weights, value_states)
+    attn_output = attn_output.transpose(1, 2).contiguous()
+
+    return attn_output, attn_weights
+
+
+class GemmaAttention(nn.Module):
+    """Multi-headed attention from 'Attention Is All You Need' paper"""
+
+    def __init__(self, config: GemmaConfig, layer_idx: int):
+        super().__init__()
+        self.config = config
+        self.layer_idx = layer_idx
+        self.head_dim = getattr(config, "head_dim", config.hidden_size // config.num_attention_heads)
+        self.num_key_value_groups = config.num_attention_heads // config.num_key_value_heads
+        self.scaling = self.head_dim**-0.5
+        self.attention_dropout = config.attention_dropout
+        self.is_causal = True
+
+        self.q_proj = nn.Linear(
+            config.hidden_size, config.num_attention_heads * self.head_dim, bias=config.attention_bias
+        )
+        self.k_proj = nn.Linear(
+            config.hidden_size, config.num_key_value_heads * self.head_dim, bias=config.attention_bias
+        )
+        self.v_proj = nn.Linear(
+            config.hidden_size, config.num_key_value_heads * self.head_dim, bias=config.attention_bias
+        )
+        self.o_proj = nn.Linear(
+            config.num_attention_heads * self.head_dim, config.hidden_size, bias=config.attention_bias
+        )
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        position_embeddings: tuple[torch.Tensor, torch.Tensor],
+        attention_mask: Optional[torch.Tensor],
+        past_key_value: Optional[Cache] = None,
+        cache_position: Optional[torch.LongTensor] = None,
+        use_cache: bool = False,
+        **kwargs: Unpack[FlashAttentionKwargs],
+    ) -> tuple[torch.Tensor, Optional[torch.Tensor], Optional[tuple[torch.Tensor]]]:        
+        input_shape = hidden_states.shape[:-1]
+        hidden_shape = (*input_shape, -1, self.head_dim)
+
+        query_states = self.q_proj(hidden_states).view(hidden_shape).transpose(1, 2)
+        key_states = self.k_proj(hidden_states).view(hidden_shape).transpose(1, 2)
+        value_states = self.v_proj(hidden_states).view(hidden_shape).transpose(1, 2)
+
+        cos, sin = position_embeddings
+        query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin)
+
+        # Use cache if provided
+        if past_key_value is not None:
+            if use_cache:
+                # sin and cos are specific to RoPE models; cache_position needed for the static cache
+                cache_kwargs = {"sin": sin, "cos": cos, "cache_position": cache_position}
+                key_states, value_states = past_key_value.update(key_states, value_states, self.layer_idx, cache_kwargs)
+            else:
+                key_states = torch.cat([past_key_value[self.layer_idx][0], key_states], dim=2)
+                value_states = torch.cat([past_key_value[self.layer_idx][1], value_states], dim=2)
+
+        attention_interface: Callable = eager_attention_forward
+        if self.config._attn_implementation != "eager":
+            attention_interface = ALL_ATTENTION_FUNCTIONS[self.config._attn_implementation]
+
+        attn_output, attn_weights = attention_interface(
+            self,
+            query_states,
+            key_states,
+            value_states,
+            attention_mask,
+            dropout=0.0 if not self.training else self.attention_dropout,
+            scaling=self.scaling,
+            **kwargs,
+        )
+
+        attn_output = attn_output.reshape(*input_shape, -1).contiguous()
+        attn_output = self.o_proj(attn_output)
+        return attn_output, attn_weights
+
+
+class GemmaDecoderLayer(GradientCheckpointingLayer):
+    def __init__(self, config: GemmaConfig, layer_idx: int):
+        super().__init__()
+        self.hidden_size = config.hidden_size
+
+        self.self_attn = GemmaAttention(config=config, layer_idx=layer_idx)
+
+        self.mlp = GemmaMLP(config)
+        cond_dim = getattr(config, 'adarms_cond_dim', None) if getattr(config, 'use_adarms', False) else None
+        self.input_layernorm = GemmaRMSNorm(config.hidden_size, eps=config.rms_norm_eps, cond_dim=cond_dim)
+        self.post_attention_layernorm = GemmaRMSNorm(config.hidden_size, eps=config.rms_norm_eps, cond_dim=cond_dim)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_value: Optional[Cache] = None,
+        output_attentions: Optional[bool] = False,
+        use_cache: Optional[bool] = False,
+        cache_position: Optional[torch.LongTensor] = None,
+        position_embeddings: Optional[tuple[torch.Tensor, torch.Tensor]] = None,  # necessary, but kept here for BC
+        adarms_cond: Optional[torch.Tensor] = None,
+        **kwargs: Unpack[FlashAttentionKwargs],
+    ) -> tuple[torch.FloatTensor, Optional[tuple[torch.FloatTensor, torch.FloatTensor]]]:
+        residual = hidden_states
+        hidden_states, gate = self.input_layernorm(hidden_states, adarms_cond)
+
+        # Self Attention
+        hidden_states, self_attn_weights = self.self_attn(
+            hidden_states=hidden_states,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            past_key_value=past_key_value,
+            output_attentions=output_attentions,
+            use_cache=use_cache,
+            cache_position=cache_position,
+            position_embeddings=position_embeddings,
+            **kwargs,
+        )
+        hidden_states = _gated_residual(residual, hidden_states, gate)
+
+        # Fully Connected
+        residual = hidden_states
+        hidden_states, gate = self.post_attention_layernorm(hidden_states, adarms_cond)
+        hidden_states = self.mlp(hidden_states)
+        hidden_states = _gated_residual(residual, hidden_states, gate)
+
+        outputs = (hidden_states,)
+        if output_attentions:
+            outputs += (self_attn_weights,)
+
+        return outputs
+
+
+@auto_docstring
+class GemmaPreTrainedModel(PreTrainedModel):
+    config_class = GemmaConfig
+    base_model_prefix = "model"
+    supports_gradient_checkpointing = True
+    _no_split_modules = ["GemmaDecoderLayer"]
+    _skip_keys_device_placement = ["past_key_values"]
+    _supports_flash_attn_3 = True
+    _supports_flash_attn_2 = True
+    _supports_sdpa = True
+    _supports_flex_attn = True
+    _supports_cache_class = True
+    _supports_quantized_cache = True
+    _supports_static_cache = True
+    _supports_attention_backend = True
+
+    def _init_weights(self, module):
+        std = self.config.initializer_range
+        if isinstance(module, nn.Linear):
+            module.weight.data.normal_(mean=0.0, std=std)
+            if module.bias is not None:
+                module.bias.data.zero_()
+        elif isinstance(module, nn.Embedding):
+            module.weight.data.normal_(mean=0.0, std=std)
+            if module.padding_idx is not None:
+                module.weight.data[module.padding_idx].zero_()
+        elif isinstance(module, GemmaRMSNorm):
+            if hasattr(module, 'weight'):
+                module.weight.data.fill_(1.0)
+
+
+@auto_docstring
+class GemmaModel(GemmaPreTrainedModel):
+    def __init__(self, config: GemmaConfig):
+        super().__init__(config)
+        self.padding_idx = config.pad_token_id
+        self.vocab_size = config.vocab_size
+
+        self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx)
+        self.layers = nn.ModuleList(
+            [GemmaDecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers)]
+        )
+
+        cond_dim = getattr(config, 'adarms_cond_dim', None) if getattr(config, 'use_adarms', False) else None
+        self.norm = GemmaRMSNorm(config.hidden_size, eps=config.rms_norm_eps, cond_dim=cond_dim)
+        self.rotary_emb = GemmaRotaryEmbedding(config=config)
+        self.gradient_checkpointing = False
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def get_input_embeddings(self):
+        return self.embed_tokens
+
+    def set_input_embeddings(self, value):
+        self.embed_tokens = value
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: Optional[torch.LongTensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[Cache] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        cache_position: Optional[torch.LongTensor] = None,
+        adarms_cond: Optional[torch.Tensor] = None,
+        **kwargs: Unpack[FlashAttentionKwargs],
+    ) -> BaseModelOutputWithPast:
+        """
+        adarms_cond (`torch.Tensor` of shape `(batch_size, cond_dim)`, *optional*):
+            Condition for ADARMS.
+        """
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+        use_cache = use_cache if use_cache is not None else self.config.use_cache
+
+        if (input_ids is None) ^ (inputs_embeds is not None):
+            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")
+
+        if self.gradient_checkpointing and self.training and use_cache:
+            logger.warning_once(
+                "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`."
+            )
+            use_cache = False
+
+        if inputs_embeds is None:
+            inputs_embeds = self.embed_tokens(input_ids)
+
+        if use_cache and past_key_values is None:
+            past_key_values = DynamicCache()
+
+        if cache_position is None:
+            past_seen_tokens = past_key_values.get_seq_length() if past_key_values is not None else 0
+            cache_position = torch.arange(
+                past_seen_tokens, past_seen_tokens + inputs_embeds.shape[1], device=inputs_embeds.device
+            )
+
+        if position_ids is None:
+            position_ids = cache_position.unsqueeze(0)
+
+        causal_mask = create_causal_mask(
+            config=self.config,
+            input_embeds=inputs_embeds,
+            attention_mask=attention_mask,
+            cache_position=cache_position,
+            past_key_values=past_key_values,
+            position_ids=position_ids,
+        )
+
+        # embed positions
+        hidden_states = inputs_embeds
+        # Convert to bfloat16 if the first layer uses bfloat16
+        if len(self.layers) > 0 and self.layers[0].self_attn.q_proj.weight.dtype == torch.bfloat16:
+            hidden_states = hidden_states.to(torch.bfloat16)
+
+        # create position embeddings to be shared across the decoder layers
+        position_embeddings = self.rotary_emb(hidden_states, position_ids)
+
+        # normalized
+        # Gemma downcasts the below to float16, causing sqrt(3072)=55.4256 to become 55.5
+        # See https://github.com/huggingface/transformers/pull/29402
+        normalizer = torch.tensor(self.config.hidden_size**0.5, dtype=hidden_states.dtype)
+        #hidden_states = hidden_states * normalizer
+
+        # decoder layers
+        all_hidden_states = () if output_hidden_states else None
+        all_self_attns = () if output_attentions else None
+
+        for decoder_layer in self.layers[: self.config.num_hidden_layers]:
+            if output_hidden_states:
+                all_hidden_states += (hidden_states,)
+
+            layer_outputs = decoder_layer(
+                hidden_states,
+                attention_mask=causal_mask,
+                position_ids=position_ids,
+                past_key_value=past_key_values,
+                output_attentions=output_attentions,
+                use_cache=use_cache,
+                cache_position=cache_position,
+                position_embeddings=position_embeddings,
+                adarms_cond=adarms_cond,
+                **kwargs,
+            )
+
+            hidden_states = layer_outputs[0]
+
+            if output_attentions:
+                all_self_attns += (layer_outputs[1],)
+
+        hidden_states, _ = self.norm(hidden_states, adarms_cond)
+
+        # add hidden states from the last decoder layer
+        if output_hidden_states:
+            all_hidden_states += (hidden_states,)
+
+        return BaseModelOutputWithPast(
+            last_hidden_state=hidden_states,
+            past_key_values=past_key_values if use_cache else None,
+            hidden_states=all_hidden_states,
+            attentions=all_self_attns,
+        )
+
+
+class KwargsForCausalLM(FlashAttentionKwargs, LossKwargs): ...
+
+
+@auto_docstring
+class GemmaForCausalLM(GemmaPreTrainedModel, GenerationMixin):
+    _tied_weights_keys = ["lm_head.weight"]
+    _tp_plan = {"lm_head": "colwise_rep"}
+    _pp_plan = {"lm_head": (["hidden_states"], ["logits"])}
+
+    def __init__(self, config):
+        super().__init__(config)
+        self.model = GemmaModel(config)
+        self.vocab_size = config.vocab_size
+        self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def get_input_embeddings(self):
+        return self.model.embed_tokens
+
+    def set_input_embeddings(self, value):
+        self.model.embed_tokens = value
+
+    def get_output_embeddings(self):
+        return self.lm_head
+
+    def set_output_embeddings(self, new_embeddings):
+        self.lm_head = new_embeddings
+
+    def set_decoder(self, decoder):
+        self.model = decoder
+
+    def get_decoder(self):
+        return self.model
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: Optional[torch.LongTensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[Cache] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        labels: Optional[torch.LongTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        cache_position: Optional[torch.LongTensor] = None,
+        logits_to_keep: Union[int, torch.Tensor] = 0,
+        adarms_cond: Optional[torch.Tensor] = None,
+        **kwargs: Unpack[KwargsForCausalLM],
+    ) -> CausalLMOutputWithPast:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
+            Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
+            config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
+            (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
+
+        adarms_cond (`torch.Tensor` of shape `(batch_size, cond_dim)`, *optional*):
+            Condition for ADARMS.
+
+        Example:
+
+        ```python
+        >>> from transformers import AutoTokenizer, GemmaForCausalLM
+
+        >>> model = GemmaForCausalLM.from_pretrained("google/gemma-7b")
+        >>> tokenizer = AutoTokenizer.from_pretrained("google/gemma-7b")
+
+        >>> prompt = "What is your favorite condiment?"
+        >>> inputs = tokenizer(prompt, return_tensors="pt")
+
+        >>> # Generate
+        >>> generate_ids = model.generate(inputs.input_ids, max_length=30)
+        >>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
+        "What is your favorite condiment?"
+        ```"""
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        # decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn)
+        outputs: BaseModelOutputWithPast = self.model(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            use_cache=use_cache,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            cache_position=cache_position,
+            adarms_cond=adarms_cond,
+            **kwargs,
+        )
+
+        hidden_states = outputs.last_hidden_state
+        # Only compute necessary logits, and do not upcast them to float if we are not computing the loss
+        slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
+        logits = self.lm_head(hidden_states[:, slice_indices, :])
+
+        loss = None
+        if labels is not None:
+            loss = self.loss_function(logits=logits, labels=labels, vocab_size=self.config.vocab_size, **kwargs)
+
+        return CausalLMOutputWithPast(
+            loss=loss,
+            logits=logits,
+            past_key_values=outputs.past_key_values,
+            hidden_states=outputs.hidden_states,
+            attentions=outputs.attentions,
+        )
+
+
+@auto_docstring(
+    custom_intro="""
+    The Gemma Model transformer with a sequence classification head on top (linear layer).
+
+    [`GemmaForSequenceClassification`] uses the last token in order to do the classification, as other causal models
+    (e.g. GPT-2) do.
+
+    Since it does classification on the last token, it requires to know the position of the last token. If a
+    `pad_token_id` is defined in the configuration, it finds the last token that is not a padding token in each row. If
+    no `pad_token_id` is defined, it simply takes the last value in each row of the batch. Since it cannot guess the
+    padding tokens when `inputs_embeds` are passed instead of `input_ids`, it does the same (take the last value in
+    each row of the batch).
+    """
+)
+class GemmaForSequenceClassification(GemmaPreTrainedModel):
+    def __init__(self, config):
+        super().__init__(config)
+        self.num_labels = config.num_labels
+        self.model = GemmaModel(config)
+        self.score = nn.Linear(config.hidden_size, self.num_labels, bias=False)
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def get_input_embeddings(self):
+        return self.model.embed_tokens
+
+    def set_input_embeddings(self, value):
+        self.model.embed_tokens = value
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: Optional[torch.LongTensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[Cache] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        labels: Optional[torch.LongTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        adarms_cond: Optional[torch.Tensor] = None,
+    ) -> SequenceClassifierOutputWithPast:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
+            Labels for computing the sequence classification/regression loss. Indices should be in `[0, ...,
+            config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
+            `config.num_labels > 1` a classification loss is computed (Cross-Entropy).
+
+        adarms_cond (`torch.Tensor` of shape `(batch_size, cond_dim)`, *optional*):
+            Condition for ADARMS.
+        """
+
+        transformer_outputs: BaseModelOutputWithPast = self.model(
+            input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            use_cache=use_cache,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            adarms_cond=adarms_cond,
+        )
+        hidden_states = transformer_outputs.last_hidden_state
+        logits = self.score(hidden_states)
+
+        if input_ids is not None:
+            batch_size = input_ids.shape[0]
+        else:
+            batch_size = inputs_embeds.shape[0]
+
+        if self.config.pad_token_id is None and batch_size != 1:
+            raise ValueError("Cannot handle batch sizes > 1 if no padding token is defined.")
+        if self.config.pad_token_id is None:
+            last_non_pad_token = -1
+        elif input_ids is not None:
+            # To handle both left- and right- padding, we take the rightmost token that is not equal to pad_token_id
+            non_pad_mask = (input_ids != self.config.pad_token_id).to(logits.device, torch.int32)
+            token_indices = torch.arange(input_ids.shape[-1], device=logits.device, dtype=torch.int32)
+            last_non_pad_token = (token_indices * non_pad_mask).argmax(-1)
+        else:
+            last_non_pad_token = -1
+            logger.warning_once(
+                f"{self.__class__.__name__} will not detect padding tokens in `inputs_embeds`. Results may be "
+                "unexpected if using padding tokens in conjunction with `inputs_embeds.`"
+            )
+
+        pooled_logits = logits[torch.arange(batch_size, device=logits.device), last_non_pad_token]
+
+        loss = None
+        if labels is not None:
+            loss = self.loss_function(logits=logits, labels=labels, pooled_logits=pooled_logits, config=self.config)
+
+        return SequenceClassifierOutputWithPast(
+            loss=loss,
+            logits=pooled_logits,
+            past_key_values=transformer_outputs.past_key_values,
+            hidden_states=transformer_outputs.hidden_states,
+            attentions=transformer_outputs.attentions,
+        )
+
+
+@auto_docstring
+class GemmaForTokenClassification(GemmaPreTrainedModel):
+    def __init__(self, config):
+        super().__init__(config)
+        self.num_labels = config.num_labels
+        self.model = GemmaModel(config)
+        if getattr(config, "classifier_dropout", None) is not None:
+            classifier_dropout = config.classifier_dropout
+        elif getattr(config, "hidden_dropout", None) is not None:
+            classifier_dropout = config.hidden_dropout
+        else:
+            classifier_dropout = 0.1
+        self.dropout = nn.Dropout(classifier_dropout)
+        self.score = nn.Linear(config.hidden_size, config.num_labels)
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def get_input_embeddings(self):
+        return self.model.embed_tokens
+
+    def set_input_embeddings(self, value):
+        self.model.embed_tokens = value
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: Optional[torch.LongTensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[Cache] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        labels: Optional[torch.LongTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        adarms_cond: Optional[torch.Tensor] = None,
+    ) -> TokenClassifierOutput:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
+            Labels for computing the sequence classification/regression loss. Indices should be in `[0, ...,
+            config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
+            `config.num_labels > 1` a classification loss is computed (Cross-Entropy).
+
+        adarms_cond (`torch.Tensor` of shape `(batch_size, cond_dim)`, *optional*):
+            Condition for ADARMS.
+        """
+
+        outputs: BaseModelOutputWithPast = self.model(
+            input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            use_cache=use_cache,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            adarms_cond=adarms_cond,
+        )
+        sequence_output = outputs.last_hidden_state
+        sequence_output = self.dropout(sequence_output)
+        logits = self.score(sequence_output)
+
+        loss = None
+        if labels is not None:
+            loss = self.loss_function(logits, labels, self.config)
+
+        return TokenClassifierOutput(
+            loss=loss,
+            logits=logits,
+            hidden_states=outputs.hidden_states,
+            attentions=outputs.attentions,
+        )
+
+
+__all__ = [
+    "GemmaModel",
+    "GemmaForCausalLM",
+    "GemmaForSequenceClassification",
+    "GemmaForTokenClassification",
+    "GemmaPreTrainedModel",
+]
diff --git a/openpi_runtime/openpi/models_pytorch/transformers_replace/models/paligemma/modeling_paligemma.py b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/paligemma/modeling_paligemma.py
new file mode 100644
index 0000000000000000000000000000000000000000..fbf0e948909044f1f97ce053cce4ff0fee0378e8
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/paligemma/modeling_paligemma.py
@@ -0,0 +1,622 @@
+# coding=utf-8
+# Copyright 2024 the HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""PyTorch PaliGemmamodel."""
+
+from dataclasses import dataclass
+from typing import Optional, Union
+
+import torch
+import torch.utils.checkpoint
+from torch import nn
+
+from ...cache_utils import Cache, HybridCache, StaticCache
+from ...generation import GenerationMixin
+from ...modeling_flash_attention_utils import FlashAttentionKwargs
+from ...modeling_outputs import BaseModelOutputWithPast
+from ...modeling_utils import PreTrainedModel
+from ...processing_utils import Unpack
+from ...utils import LossKwargs, ModelOutput, auto_docstring, can_return_tuple, is_torchdynamo_compiling, logging
+from ..auto import AutoModel
+from .configuration_paligemma import PaliGemmaConfig
+
+
+logger = logging.get_logger(__name__)
+
+
+@dataclass
+@auto_docstring(
+    custom_intro="""
+    Base class for Paligemma outputs, with hidden states and attentions.
+    """
+)
+class PaligemmaModelOutputWithPast(BaseModelOutputWithPast):
+    r"""
+    past_key_values (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`):
+        Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of shape
+        `(batch_size, num_heads, sequence_length, embed_size_per_head)`)
+
+        Contains pre-computed hidden-states (key and values in the self-attention blocks) that can be used (see
+        `past_key_values` input) to speed up sequential decoding.
+    image_hidden_states (`torch.FloatTensor`, *optional*):
+        A `torch.FloatTensor` of size `(batch_size, num_images, sequence_length, hidden_size)`.
+        image_hidden_states of the model produced by the vision encoder and after projecting the last hidden state.
+    """
+
+    image_hidden_states: Optional[torch.FloatTensor] = None
+
+
+@dataclass
+@auto_docstring(
+    custom_intro="""
+    Base class for PaliGemma causal language model (or autoregressive) outputs.
+    """
+)
+class PaliGemmaCausalLMOutputWithPast(ModelOutput):
+    r"""
+    loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided):
+        Language modeling loss (for next-token prediction).
+    logits (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.text_config.vocab_size)`):
+        Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
+    past_key_values (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`):
+        Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of shape
+        `(batch_size, num_heads, sequence_length, embed_size_per_head)`)
+
+        Contains pre-computed hidden-states (key and values in the self-attention blocks) that can be used (see
+        `past_key_values` input) to speed up sequential decoding.
+    image_hidden_states (`torch.FloatTensor`, *optional*):
+        A `torch.FloatTensor` of size `(batch_size, num_images, sequence_length, hidden_size)`.
+        image_hidden_states of the model produced by the vision encoder after projecting last hidden state.
+    """
+
+    loss: Optional[torch.FloatTensor] = None
+    logits: Optional[torch.FloatTensor] = None
+    past_key_values: Optional[Union[list[torch.FloatTensor], Cache]] = None
+    hidden_states: Optional[tuple[torch.FloatTensor]] = None
+    attentions: Optional[tuple[torch.FloatTensor]] = None
+    image_hidden_states: Optional[torch.FloatTensor] = None
+
+
+class PaliGemmaMultiModalProjector(nn.Module):
+    def __init__(self, config: PaliGemmaConfig):
+        super().__init__()
+        self.linear = nn.Linear(config.vision_config.hidden_size, config.vision_config.projection_dim, bias=True)
+
+    def forward(self, image_features):
+        hidden_states = self.linear(image_features)
+
+        return hidden_states
+
+
+@auto_docstring
+class PaliGemmaPreTrainedModel(PreTrainedModel):
+    config_class = PaliGemmaConfig
+    base_model_prefix = ""
+    supports_gradient_checkpointing = True
+    _no_split_modules = ["PaliGemmaMultiModalProjector"]
+    _skip_keys_device_placement = "past_key_values"
+    _supports_cache_class = True
+    _supports_quantized_cache = True
+    _supports_static_cache = True
+    _supports_flash_attn_2 = True
+    _supports_sdpa = True
+    _supports_flex_attn = True
+    _supports_attention_backend = True
+
+    def _init_weights(self, module):
+        # important: this ported version of PaliGemmaisn't meant for training from scratch - only
+        # inference and fine-tuning
+        std = getattr(self.config, "initializer_range", self.config.get_text_config().initializer_range)
+
+        if isinstance(module, nn.Linear):
+            module.weight.data.normal_(mean=0.0, std=std)
+            if module.bias is not None:
+                module.bias.data.zero_()
+
+
+@auto_docstring(
+    custom_intro="""
+    The Base Paligemma model which consists of a vision backbone and a language model withou language modeling head.,
+    """
+)
+class PaliGemmaModel(PaliGemmaPreTrainedModel):
+    _checkpoint_conversion_mapping = {"language_model.model": "language_model"}
+    # we are filtering the logits/labels so we shouldn't divide the loss based on num_items_in_batch
+    accepts_loss_kwargs = False
+
+    def __init__(self, config: PaliGemmaConfig):
+        super().__init__(config)
+        self.vision_tower = AutoModel.from_config(config=config.vision_config)
+        self.multi_modal_projector = PaliGemmaMultiModalProjector(config)
+        self.vocab_size = config.text_config.vocab_size
+
+        language_model = AutoModel.from_config(config=config.text_config)
+        self.language_model = language_model
+
+        self.pad_token_id = self.config.pad_token_id if self.config.pad_token_id is not None else -1
+        self.post_init()
+
+    # Copied from transformers.models.llava.modeling_llava.LlavaModel.get_input_embeddings with Llava->PaliGemma
+    def get_input_embeddings(self):
+        return self.language_model.get_input_embeddings()
+
+    # Copied from transformers.models.llava.modeling_llava.LlavaModel.set_input_embeddings with Llava->PaliGemma
+    def set_input_embeddings(self, value):
+        self.language_model.set_input_embeddings(value)
+
+    def set_decoder(self, decoder):
+        self.language_model = decoder
+
+    def get_decoder(self):
+        return self.language_model
+
+    def _update_causal_mask(
+        self,
+        attention_mask,
+        token_type_ids=None,
+        past_key_values=None,
+        cache_position=None,
+        input_tensor=None,
+        is_training: Optional[bool] = None,
+    ):
+        if self.config.text_config._attn_implementation == "flash_attention_2":
+            if attention_mask is not None and 0.0 in attention_mask:
+                return attention_mask
+            return None
+        is_training = is_training if is_training is not None else self.training
+        using_static_cache = isinstance(past_key_values, StaticCache)
+        min_dtype = torch.finfo(self.dtype).min
+        if input_tensor is None:
+            input_tensor = attention_mask
+
+        inputs_lead_dim, sequence_length = input_tensor.shape[:2]
+        if using_static_cache:
+            target_length = past_key_values.get_max_cache_shape()
+        elif isinstance(past_key_values, HybridCache):
+            target_length = past_key_values.get_max_cache_shape()
+        else:
+            target_length = (
+                attention_mask.shape[-1]
+                if isinstance(attention_mask, torch.Tensor)
+                else cache_position[0] + sequence_length + 1
+            )
+
+        if attention_mask is not None and attention_mask.dim() == 4:
+            # In this case we assume that the mask comes already in inverted form and requires no inversion or slicing.
+            return attention_mask
+
+        causal_mask = torch.full(
+            (sequence_length, target_length), fill_value=min_dtype, dtype=self.dtype, device=cache_position.device
+        )
+        # Causal diagonal mask only if training, otherwise attend to the whole prefix. Training-specific attn for prefix is handled below
+        if sequence_length != 1:
+            if is_training:
+                causal_mask = torch.triu(causal_mask, diagonal=1)
+            else:
+                causal_mask[:, :sequence_length] = 0.0
+
+        causal_mask *= torch.arange(target_length, device=cache_position.device) > cache_position.reshape(-1, 1)
+        causal_mask = causal_mask[None, None, :, :].expand(inputs_lead_dim, 1, -1, -1)
+        if attention_mask is not None:
+            causal_mask = causal_mask.clone()  # copy to contiguous memory for in-place edit
+            mask_length = attention_mask.shape[-1]
+
+            # First unmask prefix tokens during training
+            if is_training:
+                if token_type_ids is None:
+                    raise ValueError("Token type ids must be provided during training")
+                causal_mask[:, :, :, :mask_length] = causal_mask[:, :, :, :mask_length].masked_fill(
+                    token_type_ids[:, None, None, :].to(causal_mask.device) == 0, 0
+                )
+
+            # Then apply padding mask (will mask pad tokens)
+            padding_mask = causal_mask[:, :, :, :mask_length] + attention_mask[:, None, None, :].to(causal_mask.device)
+            padding_mask = padding_mask == 0
+            causal_mask[:, :, :, :mask_length] = causal_mask[:, :, :, :mask_length].masked_fill(
+                padding_mask, min_dtype
+            )
+
+        return causal_mask
+
+    def get_image_features(self, pixel_values: torch.FloatTensor):
+        """
+        Obtains image last hidden states from the vision tower and apply multimodal projection.
+
+        Args:
+            pixel_values (`torch.FloatTensor]` of shape `(batch_size, channels, height, width)`)
+               The tensors corresponding to the input images.
+        Returns:
+            image_features (`torch.Tensor`): Image feature tensor of shape `(num_images, image_length, embed_dim)`).
+        """
+        image_outputs = self.vision_tower(pixel_values)
+        selected_image_feature = image_outputs.last_hidden_state
+        image_features = self.multi_modal_projector(selected_image_feature)
+        return image_features
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: torch.LongTensor = None,
+        pixel_values: torch.FloatTensor = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[Union[list[torch.FloatTensor], Cache]] = None,
+        token_type_ids: Optional[torch.LongTensor] = None,
+        cache_position: Optional[torch.LongTensor] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        labels: Optional[torch.LongTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+        **kwargs: Unpack[FlashAttentionKwargs],
+    ) -> Union[tuple, PaligemmaModelOutputWithPast]:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
+            Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
+            config.text_config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
+            (masked), the loss is only computed for the tokens with labels in `[0, ..., config.text_config.vocab_size]`.
+
+        Example:
+
+        ```python
+        >>> from PIL import Image
+        >>> import requests
+        >>> from transformers import AutoProcessor, PaliGemmaForConditionalGeneration
+
+        >>> model = PaliGemmaForConditionalGeneration.from_pretrained("google/paligemma2-3b-mix-224")
+        >>> processor = AutoProcessor.from_pretrained("google/paligemma2-3b-mix-224")
+
+        >>> prompt = "Where is the cat standing?"
+        >>> url = "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/pipeline-cat-chonk.jpeg"
+        >>> image = Image.open(requests.get(url, stream=True).raw)
+
+        >>> inputs = processor(images=image, text=prompt,  return_tensors="pt")
+
+        >>> # Generate
+        >>> generate_ids = model.generate(**inputs,)
+        >>> processor.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
+        "Where is the cat standing?\nsnow"
+        ```"""
+
+        if (input_ids is None) ^ (inputs_embeds is not None):
+            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")
+
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+        return_dict = return_dict if return_dict is not None else self.config.use_return_dict
+
+        is_training = token_type_ids is not None and labels is not None
+
+        # Replace image id woth PAD if the image token if OOV, to avoid index-errors
+        if input_ids is not None and self.config.image_token_id >= self.vocab_size:
+            special_image_mask = input_ids == self.config.image_token_id
+            llm_input_ids = input_ids.clone()
+            llm_input_ids[special_image_mask] = 0
+        else:
+            llm_input_ids = input_ids
+
+        if inputs_embeds is None:
+            inputs_embeds = self.get_input_embeddings()(llm_input_ids)
+
+        if cache_position is None:
+            past_seen_tokens = past_key_values.get_seq_length() if past_key_values is not None else 0
+            cache_position = torch.arange(
+                past_seen_tokens, past_seen_tokens + inputs_embeds.shape[1], device=inputs_embeds.device
+            )
+
+        if position_ids is None:
+            position_ids = cache_position.unsqueeze(0) + 1  # Paligemma positions are 1-indexed
+
+        # Merge text and images
+        if pixel_values is not None:
+            image_features = self.get_image_features(pixel_values)
+
+            if input_ids is None:
+                special_image_mask = inputs_embeds == self.get_input_embeddings()(
+                    torch.tensor(self.config.image_token_id, dtype=torch.long, device=inputs_embeds.device)
+                )
+            else:
+                special_image_mask = (input_ids == self.config.image_token_id).unsqueeze(-1)
+                special_image_mask = special_image_mask.expand_as(inputs_embeds).to(inputs_embeds.device)
+
+            if not is_torchdynamo_compiling() and inputs_embeds[special_image_mask].numel() != image_features.numel():
+                image_tokens_in_text = (special_image_mask).sum(dim=1).sum(dim=0)[0]
+                raise ValueError(
+                    f"Number of images does not match number of special image tokens in the input text. "
+                    f"Got {image_tokens_in_text} image tokens in the text but {image_features.shape[0] * image_features.shape[1]} "
+                    "tokens from image embeddings."
+                )
+            image_features = image_features.to(inputs_embeds.device, inputs_embeds.dtype)
+            inputs_embeds = inputs_embeds.masked_scatter(special_image_mask, image_features)
+
+        causal_mask = self._update_causal_mask(
+            attention_mask, token_type_ids, past_key_values, cache_position, inputs_embeds, is_training
+        )
+        outputs = self.language_model(
+            attention_mask=causal_mask,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            use_cache=use_cache,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=True,
+            cache_position=cache_position,
+            **kwargs,
+        )
+
+        return PaligemmaModelOutputWithPast(
+            last_hidden_state=outputs.last_hidden_state,
+            past_key_values=outputs.past_key_values,
+            hidden_states=outputs.hidden_states,
+            attentions=outputs.attentions,
+            image_hidden_states=image_features if pixel_values is not None else None,
+        )
+
+
+class KwargsForCausalLM(FlashAttentionKwargs, LossKwargs): ...
+
+
+@auto_docstring(
+    custom_intro="""
+    The Base Paligemma model which consists of a vision backbone and a language model without language modeling head.,
+    """
+)
+class PaliGemmaForConditionalGeneration(PaliGemmaPreTrainedModel, GenerationMixin):
+    _checkpoint_conversion_mapping = {
+        "^language_model.model": "model.language_model",
+        "^vision_tower": "model.vision_tower",
+        "^multi_modal_projector": "model.multi_modal_projector",
+        "^language_model.lm_head": "lm_head",
+    }
+    _tied_weights_keys = ["lm_head.weight"]
+
+    def __init__(self, config: PaliGemmaConfig):
+        super().__init__(config)
+        self.model = PaliGemmaModel(config)
+        self.lm_head = nn.Linear(config.text_config.hidden_size, config.text_config.vocab_size, bias=False)
+        self.post_init()
+
+    def get_input_embeddings(self):
+        return self.model.get_input_embeddings()
+
+    def set_input_embeddings(self, value):
+        self.model.set_input_embeddings(value)
+
+    def get_output_embeddings(self):
+        return self.lm_head
+
+    def set_output_embeddings(self, new_embeddings):
+        self.lm_head = new_embeddings
+
+    def set_decoder(self, decoder):
+        self.model.set_decoder(decoder)
+
+    def get_decoder(self):
+        return self.model.get_decoder()
+
+    def get_image_features(self, pixel_values):
+        return self.model.get_image_features(pixel_values)
+
+    # Make modules available throught conditional class for BC
+    @property
+    def language_model(self):
+        return self.model.language_model
+
+    @property
+    def vision_tower(self):
+        return self.model.vision_tower
+
+    @property
+    def multi_modal_projector(self):
+        return self.model.multi_modal_projector
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: torch.LongTensor = None,
+        pixel_values: torch.FloatTensor = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        past_key_values: Optional[Union[list[torch.FloatTensor], Cache]] = None,
+        token_type_ids: Optional[torch.LongTensor] = None,
+        cache_position: Optional[torch.LongTensor] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+        labels: Optional[torch.LongTensor] = None,
+        use_cache: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+        logits_to_keep: Union[int, torch.Tensor] = 0,
+        **kwargs: Unpack[KwargsForCausalLM],
+    ) -> Union[tuple, PaliGemmaCausalLMOutputWithPast]:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
+            Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
+            config.text_config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
+            (masked), the loss is only computed for the tokens with labels in `[0, ..., config.text_config.vocab_size]`.
+
+        Example:
+
+        ```python
+        >>> from PIL import Image
+        >>> import requests
+        >>> from transformers import AutoProcessor, PaliGemmaForConditionalGeneration
+
+        >>> model = PaliGemmaForConditionalGeneration.from_pretrained("google/paligemma2-3b-mix-224")
+        >>> processor = AutoProcessor.from_pretrained("google/paligemma2-3b-mix-224")
+
+        >>> prompt = "Where is the cat standing?"
+        >>> url = "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/pipeline-cat-chonk.jpeg"
+        >>> image = Image.open(requests.get(url, stream=True).raw)
+
+        >>> inputs = processor(images=image, text=prompt,  return_tensors="pt")
+
+        >>> # Generate
+        >>> generate_ids = model.generate(**inputs,)
+        >>> processor.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
+        "Where is the cat standing?\nsnow"
+        ```"""
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+        return_dict = return_dict if return_dict is not None else self.config.use_return_dict
+
+        outputs = self.model(
+            input_ids=input_ids,
+            pixel_values=pixel_values,
+            token_type_ids=token_type_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            use_cache=use_cache,
+            labels=labels,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=True,
+            cache_position=cache_position,
+            **kwargs,
+        )
+
+        hidden_states = outputs[0]
+        # Only compute necessary logits, and do not upcast them to float if we are not computing the loss
+        slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
+        logits = self.lm_head(hidden_states[:, slice_indices, :])
+
+        loss = None
+        if labels is not None:
+            loss = self.loss_function(
+                logits=logits, labels=labels, vocab_size=self.config.text_config.vocab_size, **kwargs
+            )
+
+        return PaliGemmaCausalLMOutputWithPast(
+            loss=loss,
+            logits=logits,
+            past_key_values=outputs.past_key_values,
+            hidden_states=outputs.hidden_states,
+            attentions=outputs.attentions,
+            image_hidden_states=outputs.image_hidden_states,
+        )
+
+    def prepare_inputs_for_generation(
+        self,
+        input_ids,
+        past_key_values=None,
+        inputs_embeds=None,
+        cache_position=None,
+        position_ids=None,
+        pixel_values=None,
+        attention_mask=None,
+        token_type_ids=None,
+        use_cache=True,
+        logits_to_keep=None,
+        labels=None,
+        **kwargs,
+    ):
+        # Overwritten -- custom `position_ids` and `pixel_values` handling
+        model_inputs = super().prepare_inputs_for_generation(
+            input_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            cache_position=cache_position,
+            use_cache=use_cache,
+            logits_to_keep=logits_to_keep,
+            token_type_ids=token_type_ids,
+            **kwargs,
+        )
+
+        # position_ids in Paligemma are 1-indexed
+        if model_inputs.get("position_ids") is not None:
+            model_inputs["position_ids"] += 1
+        # If we're in cached decoding stage, pixel values should be None because input ids do not contain special image token anymore
+        # Otherwise we need pixel values to be passed to model. NOTE: use_cache=False needs pixel_values always
+        if cache_position[0] == 0:
+            model_inputs["pixel_values"] = pixel_values
+        is_training = token_type_ids is not None and labels is not None
+        if cache_position[0] == 0 and isinstance(past_key_values, HybridCache):
+            input_tensor = inputs_embeds if inputs_embeds is not None else input_ids
+            causal_mask = self.model._update_causal_mask(
+                attention_mask, token_type_ids, past_key_values, cache_position, input_tensor, is_training
+            )
+            model_inputs["attention_mask"] = causal_mask
+
+        return model_inputs
+
+    @staticmethod
+    # Copied from transformers.models.gptj.modeling_gptj.GPTJModel._prepare_4d_causal_attention_mask_with_cache_position
+    def _prepare_4d_causal_attention_mask_with_cache_position(
+        attention_mask: torch.Tensor,
+        sequence_length: int,
+        target_length: int,
+        dtype: torch.dtype,
+        cache_position: torch.Tensor,
+        batch_size: int,
+        **kwargs,
+    ):
+        """
+        Creates a causal 4D mask of shape `(batch_size, 1, query_length, key_value_length)` from a 2D mask of shape
+        `(batch_size, key_value_length)`, or if the input `attention_mask` is already 4D, do nothing.
+
+        Args:
+            attention_mask (`torch.Tensor`):
+                A 2D attention mask of shape `(batch_size, key_value_length)` or a 4D attention mask of shape
+                `(batch_size, 1, query_length, key_value_length)`.
+            sequence_length (`int`):
+                The sequence length being processed.
+            target_length (`int`):
+                The target length: when generating with static cache, the mask should be as long as the static cache,
+                to account for the 0 padding, the part of the cache that is not filled yet.
+            dtype (`torch.dtype`):
+                The dtype to use for the 4D attention mask.
+            cache_position (`torch.Tensor`):
+                Indices depicting the position of the input sequence tokens in the sequence.
+            batch_size (`torch.Tensor`):
+                Batch size.
+        """
+        if attention_mask is not None and attention_mask.dim() == 4:
+            # In this case we assume that the mask comes already in inverted form and requires no inversion or slicing.
+            causal_mask = attention_mask
+        else:
+            min_dtype = torch.finfo(dtype).min
+            causal_mask = torch.full(
+                (sequence_length, target_length), fill_value=min_dtype, dtype=dtype, device=cache_position.device
+            )
+            if sequence_length != 1:
+                causal_mask = torch.triu(causal_mask, diagonal=1)
+            causal_mask *= torch.arange(target_length, device=cache_position.device) > cache_position.reshape(-1, 1)
+            causal_mask = causal_mask[None, None, :, :].expand(batch_size, 1, -1, -1)
+            if attention_mask is not None:
+                causal_mask = causal_mask.clone()  # copy to contiguous memory for in-place edit
+                mask_length = attention_mask.shape[-1]
+                padding_mask = causal_mask[:, :, :, :mask_length] + attention_mask[:, None, None, :].to(
+                    causal_mask.device
+                )
+                padding_mask = padding_mask == 0
+                causal_mask[:, :, :, :mask_length] = causal_mask[:, :, :, :mask_length].masked_fill(
+                    padding_mask, min_dtype
+                )
+
+        return causal_mask
+
+
+__all__ = ["PaliGemmaForConditionalGeneration", "PaliGemmaPreTrainedModel", "PaliGemmaModel"]
diff --git a/openpi_runtime/openpi/models_pytorch/transformers_replace/models/siglip/check.py b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/siglip/check.py
new file mode 100644
index 0000000000000000000000000000000000000000..4bb3c96aa57aea42b20452d35eb5ecd9f50d4d59
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/siglip/check.py
@@ -0,0 +1,4 @@
+import transformers
+
+def check_whether_transformers_replace_is_installed_correctly():
+    return transformers.__version__ == "4.53.2"
\ No newline at end of file
diff --git a/openpi_runtime/openpi/models_pytorch/transformers_replace/models/siglip/modeling_siglip.py b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/siglip/modeling_siglip.py
new file mode 100644
index 0000000000000000000000000000000000000000..3ea8acdb31ab5f29de86f4452942137ecb788a1b
--- /dev/null
+++ b/openpi_runtime/openpi/models_pytorch/transformers_replace/models/siglip/modeling_siglip.py
@@ -0,0 +1,1237 @@
+# coding=utf-8
+# Copyright 2024 Google AI and The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""PyTorch Siglip model."""
+
+import math
+import warnings
+from dataclasses import dataclass
+from typing import Any, Callable, Optional, Union
+
+import numpy as np
+import torch
+import torch.utils.checkpoint
+from torch import nn
+from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss
+from torch.nn.init import _calculate_fan_in_and_fan_out
+
+from ...activations import ACT2FN
+from ...modeling_attn_mask_utils import _prepare_4d_attention_mask
+from ...modeling_layers import GradientCheckpointingLayer
+from ...modeling_outputs import BaseModelOutput, BaseModelOutputWithPooling, ImageClassifierOutput
+from ...modeling_utils import ALL_ATTENTION_FUNCTIONS, PreTrainedModel
+from ...utils import ModelOutput, auto_docstring, can_return_tuple, logging, torch_int
+from .configuration_siglip import SiglipConfig, SiglipTextConfig, SiglipVisionConfig
+
+
+logger = logging.get_logger(__name__)
+
+
+def _trunc_normal_(tensor, mean, std, a, b):
+    # Cut & paste from PyTorch official master until it's in a few official releases - RW
+    # Method based on https://people.sc.fsu.edu/~jburkardt/presentations/truncated_normal.pdf
+    def norm_cdf(x):
+        # Computes standard normal cumulative distribution function
+        return (1.0 + math.erf(x / math.sqrt(2.0))) / 2.0
+
+    if (mean < a - 2 * std) or (mean > b + 2 * std):
+        warnings.warn(
+            "mean is more than 2 std from [a, b] in nn.init.trunc_normal_. "
+            "The distribution of values may be incorrect.",
+            stacklevel=2,
+        )
+
+    # Values are generated by using a truncated uniform distribution and
+    # then using the inverse CDF for the normal distribution.
+    # Get upper and lower cdf values
+    l = norm_cdf((a - mean) / std)
+    u = norm_cdf((b - mean) / std)
+
+    # Uniformly fill tensor with values from [l, u], then translate to
+    # [2l-1, 2u-1].
+    tensor.uniform_(2 * l - 1, 2 * u - 1)
+
+    # Use inverse cdf transform for normal distribution to get truncated
+    # standard normal
+    tensor.erfinv_()
+
+    # Transform to proper mean, std
+    tensor.mul_(std * math.sqrt(2.0))
+    tensor.add_(mean)
+
+    # Clamp to ensure it's in the proper range
+    tensor.clamp_(min=a, max=b)
+
+
+def trunc_normal_tf_(
+    tensor: torch.Tensor, mean: float = 0.0, std: float = 1.0, a: float = -2.0, b: float = 2.0
+) -> torch.Tensor:
+    """Fills the input Tensor with values drawn from a truncated
+    normal distribution. The values are effectively drawn from the
+    normal distribution :math:`\\mathcal{N}(\text{mean}, \text{std}^2)`
+    with values outside :math:`[a, b]` redrawn until they are within
+    the bounds. The method used for generating the random values works
+    best when :math:`a \\leq \text{mean} \\leq b`.
+
+    NOTE: this 'tf' variant behaves closer to Tensorflow / JAX impl where the
+    bounds [a, b] are applied when sampling the normal distribution with mean=0, std=1.0
+    and the result is subsequently scaled and shifted by the mean and std args.
+
+    Args:
+        tensor: an n-dimensional `torch.Tensor`
+        mean: the mean of the normal distribution
+        std: the standard deviation of the normal distribution
+        a: the minimum cutoff value
+        b: the maximum cutoff value
+    """
+    with torch.no_grad():
+        _trunc_normal_(tensor, 0, 1.0, a, b)
+        tensor.mul_(std).add_(mean)
+
+
+def variance_scaling_(tensor, scale=1.0, mode="fan_in", distribution="normal"):
+    fan_in, fan_out = _calculate_fan_in_and_fan_out(tensor)
+    if mode == "fan_in":
+        denom = fan_in
+    elif mode == "fan_out":
+        denom = fan_out
+    elif mode == "fan_avg":
+        denom = (fan_in + fan_out) / 2
+
+    variance = scale / denom
+
+    if distribution == "truncated_normal":
+        # constant is stddev of standard normal truncated to (-2, 2)
+        trunc_normal_tf_(tensor, std=math.sqrt(variance) / 0.87962566103423978)
+    elif distribution == "normal":
+        with torch.no_grad():
+            tensor.normal_(std=math.sqrt(variance))
+    elif distribution == "uniform":
+        bound = math.sqrt(3 * variance)
+        with torch.no_grad():
+            tensor.uniform_(-bound, bound)
+    else:
+        raise ValueError(f"invalid distribution {distribution}")
+
+
+def lecun_normal_(tensor):
+    variance_scaling_(tensor, mode="fan_in", distribution="truncated_normal")
+
+
+def default_flax_embed_init(tensor):
+    variance_scaling_(tensor, mode="fan_in", distribution="normal")
+
+
+@dataclass
+@auto_docstring(
+    custom_intro="""
+    Base class for vision model's outputs that also contains image embeddings of the pooling of the last hidden states.
+    """
+)
+# Copied from transformers.models.clip.modeling_clip.CLIPVisionModelOutput with CLIP->Siglip
+class SiglipVisionModelOutput(ModelOutput):
+    r"""
+    image_embeds (`torch.FloatTensor` of shape `(batch_size, output_dim)` *optional* returned when model is initialized with `with_projection=True`):
+        The image embeddings obtained by applying the projection layer to the pooler_output.
+    """
+
+    image_embeds: Optional[torch.FloatTensor] = None
+    last_hidden_state: Optional[torch.FloatTensor] = None
+    hidden_states: Optional[tuple[torch.FloatTensor, ...]] = None
+    attentions: Optional[tuple[torch.FloatTensor, ...]] = None
+
+
+@dataclass
+@auto_docstring(
+    custom_intro="""
+    Base class for text model's outputs that also contains a pooling of the last hidden states.
+    """
+)
+# Copied from transformers.models.clip.modeling_clip.CLIPTextModelOutput with CLIP->Siglip
+class SiglipTextModelOutput(ModelOutput):
+    r"""
+    text_embeds (`torch.FloatTensor` of shape `(batch_size, output_dim)` *optional* returned when model is initialized with `with_projection=True`):
+        The text embeddings obtained by applying the projection layer to the pooler_output.
+    """
+
+    text_embeds: Optional[torch.FloatTensor] = None
+    last_hidden_state: Optional[torch.FloatTensor] = None
+    hidden_states: Optional[tuple[torch.FloatTensor, ...]] = None
+    attentions: Optional[tuple[torch.FloatTensor, ...]] = None
+
+
+@dataclass
+@auto_docstring
+# Copied from transformers.models.clip.modeling_clip.CLIPOutput with CLIP->Siglip
+class SiglipOutput(ModelOutput):
+    r"""
+    loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `return_loss` is `True`):
+        Contrastive loss for image-text similarity.
+    logits_per_image (`torch.FloatTensor` of shape `(image_batch_size, text_batch_size)`):
+        The scaled dot product scores between `image_embeds` and `text_embeds`. This represents the image-text
+        similarity scores.
+    logits_per_text (`torch.FloatTensor` of shape `(text_batch_size, image_batch_size)`):
+        The scaled dot product scores between `text_embeds` and `image_embeds`. This represents the text-image
+        similarity scores.
+    text_embeds (`torch.FloatTensor` of shape `(batch_size, output_dim`):
+        The text embeddings obtained by applying the projection layer to the pooled output of [`SiglipTextModel`].
+    image_embeds (`torch.FloatTensor` of shape `(batch_size, output_dim`):
+        The image embeddings obtained by applying the projection layer to the pooled output of [`SiglipVisionModel`].
+    text_model_output (`BaseModelOutputWithPooling`):
+        The output of the [`SiglipTextModel`].
+    vision_model_output (`BaseModelOutputWithPooling`):
+        The output of the [`SiglipVisionModel`].
+    """
+
+    loss: Optional[torch.FloatTensor] = None
+    logits_per_image: Optional[torch.FloatTensor] = None
+    logits_per_text: Optional[torch.FloatTensor] = None
+    text_embeds: Optional[torch.FloatTensor] = None
+    image_embeds: Optional[torch.FloatTensor] = None
+    text_model_output: BaseModelOutputWithPooling = None
+    vision_model_output: BaseModelOutputWithPooling = None
+
+    def to_tuple(self) -> tuple[Any]:
+        return tuple(
+            self[k] if k not in ["text_model_output", "vision_model_output"] else getattr(self, k).to_tuple()
+            for k in self.keys()
+        )
+
+
+class SiglipVisionEmbeddings(nn.Module):
+    def __init__(self, config: SiglipVisionConfig):
+        super().__init__()
+        self.config = config
+        self.embed_dim = config.hidden_size
+        self.image_size = config.image_size
+        self.patch_size = config.patch_size
+
+        self.patch_embedding = nn.Conv2d(
+            in_channels=config.num_channels,
+            out_channels=self.embed_dim,
+            kernel_size=self.patch_size,
+            stride=self.patch_size,
+            padding="valid",
+        )
+
+        self.num_patches = (self.image_size // self.patch_size) ** 2
+        self.num_positions = self.num_patches
+        self.position_embedding = nn.Embedding(self.num_positions, self.embed_dim)
+        self.register_buffer("position_ids", torch.arange(self.num_positions).expand((1, -1)), persistent=False)
+
+    def interpolate_pos_encoding(self, embeddings: torch.Tensor, height: int, width: int) -> torch.Tensor:
+        """
+        This method allows to interpolate the pre-trained position encodings, to be able to use the model on higher resolution
+        images. This method is also adapted to support torch.jit tracing and no class embeddings.
+
+        Adapted from:
+        - https://github.com/facebookresearch/dino/blob/de9ee3df6cf39fac952ab558447af1fa1365362a/vision_transformer.py#L174-L194, and
+        - https://github.com/facebookresearch/dinov2/blob/e1277af2ba9496fbadf7aec6eba56e8d882d1e35/dinov2/models/vision_transformer.py#L179-L211
+        """
+
+        num_patches = embeddings.shape[1]
+        num_positions = self.position_embedding.weight.shape[0]
+
+        # always interpolate when tracing to ensure the exported model works for dynamic input shapes
+        if not torch.jit.is_tracing() and num_patches == num_positions and height == width:
+            return self.position_embedding(self.position_ids)
+
+        patch_pos_embed = self.position_embedding.weight.unsqueeze(0)
+
+        dim = embeddings.shape[-1]
+
+        new_height = height // self.patch_size
+        new_width = width // self.patch_size
+
+        sqrt_num_positions = torch_int(num_positions**0.5)
+        patch_pos_embed = patch_pos_embed.reshape(1, sqrt_num_positions, sqrt_num_positions, dim)
+        patch_pos_embed = patch_pos_embed.permute(0, 3, 1, 2)
+
+        patch_pos_embed = nn.functional.interpolate(
+            patch_pos_embed,
+            size=(new_height, new_width),
+            mode="bicubic",
+            align_corners=False,
+        )
+
+        patch_pos_embed = patch_pos_embed.permute(0, 2, 3, 1).view(1, -1, dim)
+        return patch_pos_embed
+
+    def forward(self, pixel_values: torch.FloatTensor, interpolate_pos_encoding=False) -> torch.Tensor:
+        _, _, height, width = pixel_values.shape
+        target_dtype = self.patch_embedding.weight.dtype
+        patch_embeds = self.patch_embedding(pixel_values.to(dtype=target_dtype))  # shape = [*, width, grid, grid]
+        embeddings = patch_embeds.flatten(2).transpose(1, 2)
+
+        if interpolate_pos_encoding:
+            embeddings = embeddings + self.interpolate_pos_encoding(embeddings, height, width)
+        else:
+            embeddings = embeddings + self.position_embedding(self.position_ids)
+        return embeddings
+
+
+# Copied from transformers.models.clip.modeling_clip.CLIPTextEmbeddings with CLIP->Siglip
+class SiglipTextEmbeddings(nn.Module):
+    def __init__(self, config: SiglipTextConfig):
+        super().__init__()
+        embed_dim = config.hidden_size
+
+        self.token_embedding = nn.Embedding(config.vocab_size, embed_dim)
+        self.position_embedding = nn.Embedding(config.max_position_embeddings, embed_dim)
+
+        # position_ids (1, len position emb) is contiguous in memory and exported when serialized
+        self.register_buffer(
+            "position_ids", torch.arange(config.max_position_embeddings).expand((1, -1)), persistent=False
+        )
+
+    def forward(
+        self,
+        input_ids: Optional[torch.LongTensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        inputs_embeds: Optional[torch.FloatTensor] = None,
+    ) -> torch.Tensor:
+        seq_length = input_ids.shape[-1] if input_ids is not None else inputs_embeds.shape[-2]
+        max_position_embedding = self.position_embedding.weight.shape[0]
+
+        if seq_length > max_position_embedding:
+            raise ValueError(
+                f"Sequence length must be less than max_position_embeddings (got `sequence length`: "
+                f"{seq_length} and max_position_embeddings: {max_position_embedding}"
+            )
+
+        if position_ids is None:
+            position_ids = self.position_ids[:, :seq_length]
+
+        if inputs_embeds is None:
+            inputs_embeds = self.token_embedding(input_ids)
+
+        position_embeddings = self.position_embedding(position_ids)
+        embeddings = inputs_embeds + position_embeddings
+
+        return embeddings
+
+
+def eager_attention_forward(
+    module: nn.Module,
+    query: torch.Tensor,
+    key: torch.Tensor,
+    value: torch.Tensor,
+    attention_mask: Optional[torch.Tensor],
+    scaling: float,
+    dropout: float = 0.0,
+    **kwargs,
+):
+    attn_weights = torch.matmul(query, key.transpose(-1, -2)) * scaling
+    if attention_mask is not None:
+        attn_weights = attn_weights + attention_mask
+
+    attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(query.dtype)
+    attn_weights = nn.functional.dropout(attn_weights, p=dropout, training=module.training)
+
+    attn_output = torch.matmul(attn_weights, value)
+    attn_output = attn_output.transpose(1, 2).contiguous()
+
+    return attn_output, attn_weights
+
+
+class SiglipAttention(nn.Module):
+    """Multi-headed attention from 'Attention Is All You Need' paper"""
+
+    def __init__(self, config):
+        super().__init__()
+        self.config = config
+        self.embed_dim = config.hidden_size
+        self.num_heads = config.num_attention_heads
+        self.head_dim = self.embed_dim // self.num_heads
+        if self.head_dim * self.num_heads != self.embed_dim:
+            raise ValueError(
+                f"embed_dim must be divisible by num_heads (got `embed_dim`: {self.embed_dim} and `num_heads`:"
+                f" {self.num_heads})."
+            )
+        self.scale = self.head_dim**-0.5
+        self.dropout = config.attention_dropout
+        self.is_causal = False
+
+        self.k_proj = nn.Linear(self.embed_dim, self.embed_dim)
+        self.v_proj = nn.Linear(self.embed_dim, self.embed_dim)
+        self.q_proj = nn.Linear(self.embed_dim, self.embed_dim)
+        self.out_proj = nn.Linear(self.embed_dim, self.embed_dim)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        attention_mask: Optional[torch.Tensor] = None,
+        output_attentions: Optional[bool] = False,
+    ) -> tuple[torch.Tensor, Optional[torch.Tensor]]:
+        """Input shape: Batch x Time x Channel"""
+
+        batch_size, seq_length, embed_dim = hidden_states.shape
+
+        queries = self.q_proj(hidden_states)
+        keys = self.k_proj(hidden_states)
+        values = self.v_proj(hidden_states)
+
+        queries = queries.view(batch_size, seq_length, self.num_heads, self.head_dim).transpose(1, 2)
+        keys = keys.view(batch_size, seq_length, self.num_heads, self.head_dim).transpose(1, 2)
+        values = values.view(batch_size, seq_length, self.num_heads, self.head_dim).transpose(1, 2)
+
+        attention_interface: Callable = eager_attention_forward
+        if self.config._attn_implementation != "eager":
+            if self.config._attn_implementation == "sdpa" and output_attentions:
+                logger.warning_once(
+                    "`torch.nn.functional.scaled_dot_product_attention` does not support `output_attentions=True`. Falling back to "
+                    'eager attention. This warning can be removed using the argument `attn_implementation="eager"` when loading the model.'
+                )
+            else:
+                attention_interface = ALL_ATTENTION_FUNCTIONS[self.config._attn_implementation]
+
+        attn_output, attn_weights = attention_interface(
+            self,
+            queries,
+            keys,
+            values,
+            attention_mask,
+            is_causal=self.is_causal,
+            scaling=self.scale,
+            dropout=0.0 if not self.training else self.dropout,
+        )
+
+        attn_output = attn_output.reshape(batch_size, seq_length, embed_dim).contiguous()
+        attn_output = self.out_proj(attn_output)
+
+        if not output_attentions:
+            attn_weights = None
+
+        return attn_output, attn_weights
+
+
+# Copied from transformers.models.clip.modeling_clip.CLIPMLP with CLIP->Siglip
+class SiglipMLP(nn.Module):
+    def __init__(self, config):
+        super().__init__()
+        self.config = config
+        self.activation_fn = ACT2FN[config.hidden_act]
+        self.fc1 = nn.Linear(config.hidden_size, config.intermediate_size)
+        self.fc2 = nn.Linear(config.intermediate_size, config.hidden_size)
+
+    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
+        hidden_states = self.fc1(hidden_states)
+        hidden_states = self.activation_fn(hidden_states)
+        hidden_states = self.fc2(hidden_states)
+        return hidden_states
+
+
+class SiglipEncoderLayer(GradientCheckpointingLayer):
+    def __init__(self, config: Union[SiglipVisionConfig, SiglipTextConfig]):
+        super().__init__()
+        self.embed_dim = config.hidden_size
+        self.layer_norm1 = nn.LayerNorm(self.embed_dim, eps=config.layer_norm_eps)
+        self.self_attn = SiglipAttention(config)
+        self.layer_norm2 = nn.LayerNorm(self.embed_dim, eps=config.layer_norm_eps)
+        self.mlp = SiglipMLP(config)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        attention_mask: torch.Tensor,
+        output_attentions: Optional[bool] = False,
+    ) -> tuple[torch.FloatTensor]:
+        """
+        Args:
+            hidden_states (`torch.FloatTensor`):
+                Input to the layer of shape `(batch, seq_len, embed_dim)`.
+            attention_mask (`torch.FloatTensor`):
+                Attention mask of shape `(batch, 1, q_len, k_v_seq_len)` where padding elements are indicated by very large negative values.
+            output_attentions (`bool`, *optional*, defaults to `False`):
+                Whether or not to return the attentions tensors of all attention layers. See `attentions` under
+                returned tensors for more detail.
+        """
+        residual = hidden_states
+
+        hidden_states = self.layer_norm1(hidden_states)
+        hidden_states, attn_weights = self.self_attn(
+            hidden_states=hidden_states,
+            attention_mask=attention_mask,
+            output_attentions=output_attentions,
+        )
+        hidden_states = residual + hidden_states
+
+        residual = hidden_states
+        hidden_states = self.layer_norm2(hidden_states)
+        hidden_states = self.mlp(hidden_states)
+        hidden_states = residual + hidden_states
+
+        outputs = (hidden_states,)
+
+        if output_attentions:
+            outputs += (attn_weights,)
+
+        return outputs
+
+
+@auto_docstring
+class SiglipPreTrainedModel(PreTrainedModel):
+    config_class = SiglipConfig
+    base_model_prefix = "siglip"
+    supports_gradient_checkpointing = True
+
+    _no_split_modules = [
+        "SiglipTextEmbeddings",
+        "SiglipEncoderLayer",
+        "SiglipVisionEmbeddings",
+        "SiglipEncoderLayer",
+        "SiglipMultiheadAttentionPoolingHead",
+    ]
+    _supports_flash_attn_2 = True
+    _supports_sdpa = True
+    _supports_flex_attn = True
+    _supports_attention_backend = True
+
+    def _init_weights(self, module):
+        """Initialize the weights"""
+        if isinstance(module, SiglipVisionEmbeddings):
+            width = (
+                self.config.vision_config.hidden_size
+                if isinstance(self.config, SiglipConfig)
+                else self.config.hidden_size
+            )
+            nn.init.normal_(module.position_embedding.weight, std=1 / np.sqrt(width))
+        elif isinstance(module, nn.Embedding):
+            default_flax_embed_init(module.weight)
+        elif isinstance(module, SiglipAttention):
+            nn.init.xavier_uniform_(module.q_proj.weight)
+            nn.init.xavier_uniform_(module.k_proj.weight)
+            nn.init.xavier_uniform_(module.v_proj.weight)
+            nn.init.xavier_uniform_(module.out_proj.weight)
+            nn.init.zeros_(module.q_proj.bias)
+            nn.init.zeros_(module.k_proj.bias)
+            nn.init.zeros_(module.v_proj.bias)
+            nn.init.zeros_(module.out_proj.bias)
+        elif isinstance(module, SiglipMLP):
+            nn.init.xavier_uniform_(module.fc1.weight)
+            nn.init.xavier_uniform_(module.fc2.weight)
+            nn.init.normal_(module.fc1.bias, std=1e-6)
+            nn.init.normal_(module.fc2.bias, std=1e-6)
+        elif isinstance(module, SiglipMultiheadAttentionPoolingHead):
+            nn.init.xavier_uniform_(module.probe.data)
+            nn.init.xavier_uniform_(module.attention.in_proj_weight.data)
+            nn.init.zeros_(module.attention.in_proj_bias.data)
+        elif isinstance(module, SiglipModel):
+            logit_scale_init = torch.log(torch.tensor(1.0))
+            module.logit_scale.data.fill_(logit_scale_init)
+            module.logit_bias.data.zero_()
+        elif isinstance(module, SiglipForImageClassification):
+            nn.init.normal_(
+                module.classifier.weight,
+                std=self.config.vision_config.hidden_size**-0.5 * self.config.initializer_factor,
+            )
+        elif isinstance(module, (nn.Linear, nn.Conv2d)):
+            lecun_normal_(module.weight)
+            if module.bias is not None:
+                nn.init.zeros_(module.bias)
+        elif isinstance(module, nn.LayerNorm):
+            module.bias.data.zero_()
+            module.weight.data.fill_(1.0)
+
+
+# Copied from transformers.models.altclip.modeling_altclip.AltCLIPEncoder with AltCLIP->Siglip
+class SiglipEncoder(nn.Module):
+    """
+    Transformer encoder consisting of `config.num_hidden_layers` self attention layers. Each layer is a
+    [`SiglipEncoderLayer`].
+
+    Args:
+        config: SiglipConfig
+    """
+
+    def __init__(self, config: SiglipConfig):
+        super().__init__()
+        self.config = config
+        self.layers = nn.ModuleList([SiglipEncoderLayer(config) for _ in range(config.num_hidden_layers)])
+        self.gradient_checkpointing = False
+
+    # Ignore copy
+    @can_return_tuple
+    def forward(
+        self,
+        inputs_embeds,
+        attention_mask: Optional[torch.Tensor] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+    ) -> BaseModelOutput:
+        r"""
+        Args:
+            inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`):
+                Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation.
+                This is useful if you want more control over how to convert `input_ids` indices into associated vectors
+                than the model's internal embedding lookup matrix.
+            attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*):
+                Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:
+
+                - 1 for tokens that are **not masked**,
+                - 0 for tokens that are **masked**.
+
+                [What are attention masks?](../glossary#attention-mask)
+            output_attentions (`bool`, *optional*):
+                Whether or not to return the attentions tensors of all attention layers. See `attentions` under
+                returned tensors for more detail.
+            output_hidden_states (`bool`, *optional*):
+                Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors
+                for more detail.
+            return_dict (`bool`, *optional*):
+                Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
+        """
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        encoder_states = () if output_hidden_states else None
+        all_attentions = () if output_attentions else None
+
+        hidden_states = inputs_embeds
+        for encoder_layer in self.layers:
+            if output_hidden_states:
+                encoder_states = encoder_states + (hidden_states,)
+
+            layer_outputs = encoder_layer(
+                hidden_states,
+                attention_mask,
+                output_attentions=output_attentions,
+            )
+
+            hidden_states = layer_outputs[0]
+
+            if output_attentions:
+                all_attentions = all_attentions + (layer_outputs[1],)
+
+        if output_hidden_states:
+            encoder_states = encoder_states + (hidden_states,)
+
+        return BaseModelOutput(
+            last_hidden_state=hidden_states,
+            hidden_states=encoder_states,
+            attentions=all_attentions,
+        )
+
+
+class SiglipTextTransformer(nn.Module):
+    def __init__(self, config: SiglipTextConfig):
+        super().__init__()
+        self.config = config
+        embed_dim = config.hidden_size
+        self.embeddings = SiglipTextEmbeddings(config)
+        self.encoder = SiglipEncoder(config)
+        self.final_layer_norm = nn.LayerNorm(embed_dim, eps=config.layer_norm_eps)
+
+        self.head = nn.Linear(embed_dim, config.projection_size)
+        self._use_flash_attention_2 = config._attn_implementation == "flash_attention_2"
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: Optional[torch.Tensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.Tensor] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+    ) -> BaseModelOutputWithPooling:
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        if input_ids is None:
+            raise ValueError("You have to specify input_ids")
+
+        input_shape = input_ids.size()
+        input_ids = input_ids.view(-1, input_shape[-1])
+
+        hidden_states = self.embeddings(input_ids=input_ids, position_ids=position_ids)
+
+        # note: SigLIP's text model does not use a causal mask, unlike the original CLIP model.
+        # expand attention_mask
+        if attention_mask is not None and not self._use_flash_attention_2:
+            # [batch_size, seq_len] -> [batch_size, 1, tgt_seq_len, src_seq_len]
+            attention_mask = _prepare_4d_attention_mask(attention_mask, hidden_states.dtype)
+
+        encoder_outputs: BaseModelOutput = self.encoder(
+            inputs_embeds=hidden_states,
+            attention_mask=attention_mask,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+        )
+
+        last_hidden_state = encoder_outputs.last_hidden_state
+        last_hidden_state = self.final_layer_norm(last_hidden_state)
+
+        # Assuming "sticky" EOS tokenization, last token is always EOS.
+        pooled_output = last_hidden_state[:, -1, :]
+        pooled_output = self.head(pooled_output)
+
+        return BaseModelOutputWithPooling(
+            last_hidden_state=last_hidden_state,
+            pooler_output=pooled_output,
+            hidden_states=encoder_outputs.hidden_states,
+            attentions=encoder_outputs.attentions,
+        )
+
+
+@auto_docstring(
+    custom_intro="""
+    The text model from SigLIP without any head or projection on top.
+    """
+)
+class SiglipTextModel(SiglipPreTrainedModel):
+    config_class = SiglipTextConfig
+
+    def __init__(self, config: SiglipTextConfig):
+        super().__init__(config)
+        self.text_model = SiglipTextTransformer(config)
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def get_input_embeddings(self) -> nn.Module:
+        return self.text_model.embeddings.token_embedding
+
+    def set_input_embeddings(self, value):
+        self.text_model.embeddings.token_embedding = value
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: Optional[torch.Tensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.Tensor] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+    ) -> BaseModelOutputWithPooling:
+        r"""
+        Examples:
+
+        ```python
+        >>> from transformers import AutoTokenizer, SiglipTextModel
+
+        >>> model = SiglipTextModel.from_pretrained("google/siglip-base-patch16-224")
+        >>> tokenizer = AutoTokenizer.from_pretrained("google/siglip-base-patch16-224")
+
+        >>> # important: make sure to set padding="max_length" as that's how the model was trained
+        >>> inputs = tokenizer(["a photo of a cat", "a photo of a dog"], padding="max_length", return_tensors="pt")
+
+        >>> outputs = model(**inputs)
+        >>> last_hidden_state = outputs.last_hidden_state
+        >>> pooled_output = outputs.pooler_output  # pooled (EOS token) states
+        ```"""
+
+        return self.text_model(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+        )
+
+
+class SiglipVisionTransformer(nn.Module):
+    def __init__(self, config: SiglipVisionConfig):
+        super().__init__()
+        self.config = config
+        embed_dim = config.hidden_size
+
+        self.embeddings = SiglipVisionEmbeddings(config)
+        self.encoder = SiglipEncoder(config)
+        self.post_layernorm = nn.LayerNorm(embed_dim, eps=config.layer_norm_eps)
+        self.use_head = True if not hasattr(config, "vision_use_head") else config.vision_use_head
+        if self.use_head:
+            self.head = SiglipMultiheadAttentionPoolingHead(config)
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        pixel_values,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        interpolate_pos_encoding: Optional[bool] = False,
+    ) -> BaseModelOutputWithPooling:
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        hidden_states = self.embeddings(pixel_values, interpolate_pos_encoding=interpolate_pos_encoding)
+        # Convert to bfloat16 if the encoder uses bfloat16
+        if len(self.encoder.layers) > 0 and self.encoder.layers[0].self_attn.q_proj.weight.dtype == torch.bfloat16:
+            hidden_states = hidden_states.to(torch.bfloat16)
+
+        encoder_outputs: BaseModelOutput = self.encoder(
+            inputs_embeds=hidden_states,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+        )
+
+        last_hidden_state = encoder_outputs.last_hidden_state
+        last_hidden_state = self.post_layernorm(last_hidden_state)
+
+        pooler_output = self.head(last_hidden_state) if self.use_head else None
+
+        return BaseModelOutputWithPooling(
+            last_hidden_state=last_hidden_state,
+            pooler_output=pooler_output,
+            hidden_states=encoder_outputs.hidden_states,
+            attentions=encoder_outputs.attentions,
+        )
+
+
+class SiglipMultiheadAttentionPoolingHead(nn.Module):
+    """Multihead Attention Pooling."""
+
+    def __init__(self, config: SiglipVisionConfig):
+        super().__init__()
+
+        self.probe = nn.Parameter(torch.randn(1, 1, config.hidden_size))
+        self.attention = torch.nn.MultiheadAttention(config.hidden_size, config.num_attention_heads, batch_first=True)
+        self.layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
+        self.mlp = SiglipMLP(config)
+
+    def forward(self, hidden_state):
+        batch_size = hidden_state.shape[0]
+        probe = self.probe.repeat(batch_size, 1, 1)
+
+        hidden_state = self.attention(probe, hidden_state, hidden_state)[0]
+
+        residual = hidden_state
+        hidden_state = self.layernorm(hidden_state)
+        hidden_state = residual + self.mlp(hidden_state)
+
+        return hidden_state[:, 0]
+
+
+@auto_docstring(
+    custom_intro="""
+    The vision model from SigLIP without any head or projection on top.
+    """
+)
+class SiglipVisionModel(SiglipPreTrainedModel):
+    config_class = SiglipVisionConfig
+    main_input_name = "pixel_values"
+
+    def __init__(self, config: SiglipVisionConfig):
+        super().__init__(config)
+
+        self.vision_model = SiglipVisionTransformer(config)
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def get_input_embeddings(self) -> nn.Module:
+        return self.vision_model.embeddings.patch_embedding
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        pixel_values,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        interpolate_pos_encoding: bool = False,
+    ) -> BaseModelOutputWithPooling:
+        r"""
+        Examples:
+
+        ```python
+        >>> from PIL import Image
+        >>> import requests
+        >>> from transformers import AutoProcessor, SiglipVisionModel
+
+        >>> model = SiglipVisionModel.from_pretrained("google/siglip-base-patch16-224")
+        >>> processor = AutoProcessor.from_pretrained("google/siglip-base-patch16-224")
+
+        >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
+        >>> image = Image.open(requests.get(url, stream=True).raw)
+
+        >>> inputs = processor(images=image, return_tensors="pt")
+
+        >>> outputs = model(**inputs)
+        >>> last_hidden_state = outputs.last_hidden_state
+        >>> pooled_output = outputs.pooler_output  # pooled features
+        ```"""
+
+        return self.vision_model(
+            pixel_values=pixel_values,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            interpolate_pos_encoding=interpolate_pos_encoding,
+        )
+
+
+@auto_docstring
+class SiglipModel(SiglipPreTrainedModel):
+    config_class = SiglipConfig
+
+    def __init__(self, config: SiglipConfig):
+        super().__init__(config)
+
+        if not isinstance(config.text_config, SiglipTextConfig):
+            raise TypeError(
+                "config.text_config is expected to be of type SiglipTextConfig but is of type"
+                f" {type(config.text_config)}."
+            )
+
+        if not isinstance(config.vision_config, SiglipVisionConfig):
+            raise TypeError(
+                "config.vision_config is expected to be of type SiglipVisionConfig but is of type"
+                f" {type(config.vision_config)}."
+            )
+
+        text_config = config.text_config
+        vision_config = config.vision_config
+
+        # First, initialize the text and vision models with proper attention implementation
+        text_model = SiglipTextModel._from_config(text_config)
+        vision_model = SiglipVisionModel._from_config(vision_config)
+
+        # Second, get the text and vision submodules (for backward compatibility)
+        self.text_model = text_model.text_model
+        self.vision_model = vision_model.vision_model
+
+        self.logit_scale = nn.Parameter(torch.randn(1))
+        self.logit_bias = nn.Parameter(torch.randn(1))
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    @auto_docstring
+    def get_text_features(
+        self,
+        input_ids: Optional[torch.Tensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.Tensor] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+    ) -> torch.FloatTensor:
+        r"""
+        Returns:
+            text_features (`torch.FloatTensor` of shape `(batch_size, output_dim`): The text embeddings obtained by
+            applying the projection layer to the pooled output of [`SiglipTextModel`].
+
+        Examples:
+
+        ```python
+        >>> from transformers import AutoTokenizer, AutoModel
+        >>> import torch
+
+        >>> model = AutoModel.from_pretrained("google/siglip-base-patch16-224")
+        >>> tokenizer = AutoTokenizer.from_pretrained("google/siglip-base-patch16-224")
+
+        >>> # important: make sure to set padding="max_length" as that's how the model was trained
+        >>> inputs = tokenizer(["a photo of a cat", "a photo of a dog"], padding="max_length", return_tensors="pt")
+        >>> with torch.no_grad():
+        ...     text_features = model.get_text_features(**inputs)
+        ```"""
+        # Use SigLIP model's config for some fields (if specified) instead of those of vision & text components.
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        text_outputs: BaseModelOutputWithPooling = self.text_model(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+        )
+
+        pooled_output = text_outputs.pooler_output
+
+        return pooled_output
+
+    @auto_docstring
+    def get_image_features(
+        self,
+        pixel_values: Optional[torch.FloatTensor] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        interpolate_pos_encoding: bool = False,
+    ) -> torch.FloatTensor:
+        r"""
+        Returns:
+            image_features (`torch.FloatTensor` of shape `(batch_size, output_dim`): The image embeddings obtained by
+            applying the projection layer to the pooled output of [`SiglipVisionModel`].
+
+        Examples:
+
+        ```python
+        >>> from PIL import Image
+        >>> import requests
+        >>> from transformers import AutoProcessor, AutoModel
+        >>> import torch
+
+        >>> model = AutoModel.from_pretrained("google/siglip-base-patch16-224")
+        >>> processor = AutoProcessor.from_pretrained("google/siglip-base-patch16-224")
+
+        >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
+        >>> image = Image.open(requests.get(url, stream=True).raw)
+
+        >>> inputs = processor(images=image, return_tensors="pt")
+
+        >>> with torch.no_grad():
+        ...     image_features = model.get_image_features(**inputs)
+        ```"""
+        # Use SiglipModel's config for some fields (if specified) instead of those of vision & text components.
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        vision_outputs: BaseModelOutputWithPooling = self.vision_model(
+            pixel_values=pixel_values,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            interpolate_pos_encoding=interpolate_pos_encoding,
+        )
+
+        pooled_output = vision_outputs.pooler_output
+
+        return pooled_output
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: Optional[torch.LongTensor] = None,
+        pixel_values: Optional[torch.FloatTensor] = None,
+        attention_mask: Optional[torch.Tensor] = None,
+        position_ids: Optional[torch.LongTensor] = None,
+        return_loss: Optional[bool] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        interpolate_pos_encoding: bool = False,
+    ) -> SiglipOutput:
+        r"""
+        return_loss (`bool`, *optional*):
+            Whether or not to return the contrastive loss.
+
+        Examples:
+
+        ```python
+        >>> from PIL import Image
+        >>> import requests
+        >>> from transformers import AutoProcessor, AutoModel
+        >>> import torch
+
+        >>> model = AutoModel.from_pretrained("google/siglip-base-patch16-224")
+        >>> processor = AutoProcessor.from_pretrained("google/siglip-base-patch16-224")
+
+        >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
+        >>> image = Image.open(requests.get(url, stream=True).raw)
+
+        >>> texts = ["a photo of 2 cats", "a photo of 2 dogs"]
+        >>> # important: we pass `padding=max_length` since the model was trained with this
+        >>> inputs = processor(text=texts, images=image, padding="max_length", return_tensors="pt")
+
+        >>> with torch.no_grad():
+        ...     outputs = model(**inputs)
+
+        >>> logits_per_image = outputs.logits_per_image
+        >>> probs = torch.sigmoid(logits_per_image) # these are the probabilities
+        >>> print(f"{probs[0][0]:.1%} that image 0 is '{texts[0]}'")
+        31.9% that image 0 is 'a photo of 2 cats'
+        ```"""
+        # Use SigLIP model's config for some fields (if specified) instead of those of vision & text components.
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        vision_outputs: BaseModelOutputWithPooling = self.vision_model(
+            pixel_values=pixel_values,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            interpolate_pos_encoding=interpolate_pos_encoding,
+        )
+
+        text_outputs: BaseModelOutputWithPooling = self.text_model(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+        )
+
+        image_embeds = vision_outputs.pooler_output
+        text_embeds = text_outputs.pooler_output
+
+        # normalized features
+        image_embeds = image_embeds / image_embeds.norm(p=2, dim=-1, keepdim=True)
+        text_embeds = text_embeds / text_embeds.norm(p=2, dim=-1, keepdim=True)
+
+        # cosine similarity as logits
+        logits_per_text = torch.matmul(text_embeds, image_embeds.t().to(text_embeds.device))
+
+        logit_scale, logit_bias = self.logit_scale.to(text_embeds.device), self.logit_bias.to(text_embeds.device)
+        logits_per_text = logits_per_text * logit_scale.exp() + logit_bias
+
+        logits_per_image = logits_per_text.t()
+
+        loss = None
+        if return_loss:
+            # Adapted from https://github.com/google-research/big_vision/blob/01edb81a4716f93a48be43b3a4af14e29cdb3a7f/big_vision/trainers/proj/image_text/siglip.py#L287
+            eye = torch.eye(logits_per_text.size(0), device=logits_per_text.device)
+            m1_diag1 = -torch.ones_like(logits_per_text) + 2 * eye
+            loglik = torch.nn.functional.logsigmoid(m1_diag1 * logits_per_text)
+            nll = -torch.sum(loglik, dim=-1)
+            loss = nll.mean()
+
+        return SiglipOutput(
+            loss=loss,
+            logits_per_image=logits_per_image,
+            logits_per_text=logits_per_text,
+            text_embeds=text_embeds,
+            image_embeds=image_embeds,
+            text_model_output=text_outputs,
+            vision_model_output=vision_outputs,
+        )
+
+
+@auto_docstring(
+    custom_intro="""
+    SigLIP vision encoder with an image classification head on top (a linear layer on top of the pooled final hidden states of
+    the patch tokens) e.g. for ImageNet.
+    """
+)
+class SiglipForImageClassification(SiglipPreTrainedModel):
+    main_input_name = "pixel_values"
+
+    def __init__(self, config: SiglipConfig) -> None:
+        super().__init__(config)
+
+        self.num_labels = config.num_labels
+
+        # Create the vision model with proper attention
+        # and take only vision_model submodule (for backward compatibility)
+        vision_model = SiglipVisionModel._from_config(config.vision_config)
+        self.vision_model = vision_model.vision_model
+
+        # Classifier head
+        self.classifier = (
+            nn.Linear(config.vision_config.hidden_size, config.num_labels) if config.num_labels > 0 else nn.Identity()
+        )
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        pixel_values: Optional[torch.Tensor] = None,
+        labels: Optional[torch.Tensor] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        interpolate_pos_encoding: bool = False,
+    ) -> ImageClassifierOutput:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
+            Labels for computing the image classification/regression loss. Indices should be in `[0, ...,
+            config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
+            `config.num_labels > 1` a classification loss is computed (Cross-Entropy).
+
+        Examples:
+
+        ```python
+        >>> from transformers import AutoImageProcessor, SiglipForImageClassification
+        >>> import torch
+        >>> from PIL import Image
+        >>> import requests
+
+        >>> torch.manual_seed(3)  # doctest: +IGNORE_RESULT
+        >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
+        >>> image = Image.open(requests.get(url, stream=True).raw)
+
+        >>> # note: we are loading a `SiglipModel` from the hub here,
+        >>> # so the head will be randomly initialized, hence the predictions will be random if seed is not set above.
+        >>> image_processor = AutoImageProcessor.from_pretrained("google/siglip-base-patch16-224")
+        >>> model = SiglipForImageClassification.from_pretrained("google/siglip-base-patch16-224")
+
+        >>> inputs = image_processor(images=image, return_tensors="pt")
+        >>> outputs = model(**inputs)
+        >>> logits = outputs.logits
+        >>> # model predicts one of the two classes
+        >>> predicted_class_idx = logits.argmax(-1).item()
+        >>> print("Predicted class:", model.config.id2label[predicted_class_idx])
+        Predicted class: LABEL_1
+        ```"""
+        output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
+        output_hidden_states = (
+            output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
+        )
+
+        outputs: BaseModelOutputWithPooling = self.vision_model(
+            pixel_values,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            interpolate_pos_encoding=interpolate_pos_encoding,
+        )
+
+        sequence_output = outputs.last_hidden_state
+
+        # average pool the patch tokens
+        sequence_output = torch.mean(sequence_output, dim=1)
+        # apply classifier
+        logits = self.classifier(sequence_output)
+
+        loss = None
+        if labels is not None:
+            # move labels to correct device to enable model parallelism
+            labels = labels.to(logits.device)
+            if self.config.problem_type is None:
+                if self.num_labels == 1:
+                    self.config.problem_type = "regression"
+                elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int):
+                    self.config.problem_type = "single_label_classification"
+                else:
+                    self.config.problem_type = "multi_label_classification"
+
+            if self.config.problem_type == "regression":
+                loss_fct = MSELoss()
+                if self.num_labels == 1:
+                    loss = loss_fct(logits.squeeze(), labels.squeeze())
+                else:
+                    loss = loss_fct(logits, labels)
+            elif self.config.problem_type == "single_label_classification":
+                loss_fct = CrossEntropyLoss()
+                loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
+            elif self.config.problem_type == "multi_label_classification":
+                loss_fct = BCEWithLogitsLoss()
+                loss = loss_fct(logits, labels)
+
+        return ImageClassifierOutput(
+            loss=loss,
+            logits=logits,
+            hidden_states=outputs.hidden_states,
+            attentions=outputs.attentions,
+        )
+
+
+__all__ = [
+    "SiglipModel",
+    "SiglipPreTrainedModel",
+    "SiglipTextModel",
+    "SiglipVisionModel",
+    "SiglipForImageClassification",
+]
\ No newline at end of file
diff --git a/openpi_runtime/openpi/policies/aloha_policy.py b/openpi_runtime/openpi/policies/aloha_policy.py
new file mode 100644
index 0000000000000000000000000000000000000000..f16be3334584692ba505553220ab20ff7b2719c5
--- /dev/null
+++ b/openpi_runtime/openpi/policies/aloha_policy.py
@@ -0,0 +1,202 @@
+import dataclasses
+from typing import ClassVar
+
+import einops
+import numpy as np
+
+from openpi import transforms
+
+
+def make_aloha_example() -> dict:
+    """Creates a random input example for the Aloha policy."""
+    return {
+        "state": np.ones((14,)),
+        "images": {
+            "cam_high": np.random.randint(256, size=(3, 224, 224), dtype=np.uint8),
+            "cam_low": np.random.randint(256, size=(3, 224, 224), dtype=np.uint8),
+            "cam_left_wrist": np.random.randint(256, size=(3, 224, 224), dtype=np.uint8),
+            "cam_right_wrist": np.random.randint(256, size=(3, 224, 224), dtype=np.uint8),
+        },
+        "prompt": "do something",
+    }
+
+
+@dataclasses.dataclass(frozen=True)
+class AlohaInputs(transforms.DataTransformFn):
+    """Inputs for the Aloha policy.
+
+    Expected inputs:
+    - images: dict[name, img] where img is [channel, height, width]. name must be in EXPECTED_CAMERAS.
+    - state: [14]
+    - actions: [action_horizon, 14]
+    """
+
+    # If true, this will convert the joint and gripper values from the standard Aloha space to
+    # the space used by the pi internal runtime which was used to train the base model.
+    adapt_to_pi: bool = True
+
+    # The expected cameras names. All input cameras must be in this set. Missing cameras will be
+    # replaced with black images and the corresponding `image_mask` will be set to False.
+    EXPECTED_CAMERAS: ClassVar[tuple[str, ...]] = ("cam_high", "cam_low", "cam_left_wrist", "cam_right_wrist")
+
+    def __call__(self, data: dict) -> dict:
+        data = _decode_aloha(data, adapt_to_pi=self.adapt_to_pi)
+
+        in_images = data["images"]
+        if set(in_images) - set(self.EXPECTED_CAMERAS):
+            raise ValueError(f"Expected images to contain {self.EXPECTED_CAMERAS}, got {tuple(in_images)}")
+
+        # Assume that base image always exists.
+        base_image = in_images["cam_high"]
+
+        images = {
+            "base_0_rgb": base_image,
+        }
+        image_masks = {
+            "base_0_rgb": np.True_,
+        }
+
+        # Add the extra images.
+        extra_image_names = {
+            "left_wrist_0_rgb": "cam_left_wrist",
+            "right_wrist_0_rgb": "cam_right_wrist",
+        }
+        for dest, source in extra_image_names.items():
+            if source in in_images:
+                images[dest] = in_images[source]
+                image_masks[dest] = np.True_
+            else:
+                images[dest] = np.zeros_like(base_image)
+                image_masks[dest] = np.False_
+
+        inputs = {
+            "image": images,
+            "image_mask": image_masks,
+            "state": data["state"],
+        }
+
+        # Actions are only available during training.
+        if "actions" in data:
+            actions = np.asarray(data["actions"])
+            actions = _encode_actions_inv(actions, adapt_to_pi=self.adapt_to_pi)
+            inputs["actions"] = actions
+
+        if "prompt" in data:
+            inputs["prompt"] = data["prompt"]
+
+        return inputs
+
+
+@dataclasses.dataclass(frozen=True)
+class AlohaOutputs(transforms.DataTransformFn):
+    """Outputs for the Aloha policy."""
+
+    # If true, this will convert the joint and gripper values from the standard Aloha space to
+    # the space used by the pi internal runtime which was used to train the base model.
+    adapt_to_pi: bool = True
+
+    def __call__(self, data: dict) -> dict:
+        # Only return the first 14 dims.
+        actions = np.asarray(data["actions"][:, :14])
+        return {"actions": _encode_actions(actions, adapt_to_pi=self.adapt_to_pi)}
+
+
+def _joint_flip_mask() -> np.ndarray:
+    """Used to convert between aloha and pi joint angles."""
+    return np.array([1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1])
+
+
+def _normalize(x, min_val, max_val):
+    return (x - min_val) / (max_val - min_val)
+
+
+def _unnormalize(x, min_val, max_val):
+    return x * (max_val - min_val) + min_val
+
+
+def _gripper_to_angular(value):
+    # Aloha transforms the gripper positions into a linear space. The following code
+    # reverses this transformation to be consistent with pi0 which is pretrained in
+    # angular space.
+    #
+    # These values are coming from the Aloha code:
+    # PUPPET_GRIPPER_POSITION_OPEN, PUPPET_GRIPPER_POSITION_CLOSED
+    value = _unnormalize(value, min_val=0.01844, max_val=0.05800)
+
+    # This is the inverse of the angular to linear transformation inside the Interbotix code.
+    def linear_to_radian(linear_position, arm_length, horn_radius):
+        value = (horn_radius**2 + linear_position**2 - arm_length**2) / (2 * horn_radius * linear_position)
+        return np.arcsin(np.clip(value, -1.0, 1.0))
+
+    # The constants are taken from the Interbotix code.
+    value = linear_to_radian(value, arm_length=0.036, horn_radius=0.022)
+
+    # pi0 gripper data is normalized (0, 1) between encoder counts (2405, 3110).
+    # There are 4096 total encoder counts and aloha uses a zero of 2048.
+    # Converting this to radians means that the normalized inputs are between (0.5476, 1.6296)
+    return _normalize(value, min_val=0.5476, max_val=1.6296)
+
+
+def _gripper_from_angular(value):
+    # Convert from the gripper position used by pi0 to the gripper position that is used by Aloha.
+    # Note that the units are still angular but the range is different.
+
+    # We do not scale the output since the trossen model predictions are already in radians.
+    # See the comment in _gripper_to_angular for a derivation of the constant
+    value = value + 0.5476
+
+    # These values are coming from the Aloha code:
+    # PUPPET_GRIPPER_JOINT_OPEN, PUPPET_GRIPPER_JOINT_CLOSE
+    return _normalize(value, min_val=-0.6213, max_val=1.4910)
+
+
+def _gripper_from_angular_inv(value):
+    # Directly inverts the gripper_from_angular function.
+    value = _unnormalize(value, min_val=-0.6213, max_val=1.4910)
+    return value - 0.5476
+
+
+def _decode_aloha(data: dict, *, adapt_to_pi: bool = False) -> dict:
+    # state is [left_arm_joint_angles, left_arm_gripper, right_arm_joint_angles, right_arm_gripper]
+    # dim sizes: [6, 1, 6, 1]
+    state = np.asarray(data["state"])
+    state = _decode_state(state, adapt_to_pi=adapt_to_pi)
+
+    def convert_image(img):
+        img = np.asarray(img)
+        # Convert to uint8 if using float images.
+        if np.issubdtype(img.dtype, np.floating):
+            img = (255 * img).astype(np.uint8)
+        # Convert from [channel, height, width] to [height, width, channel].
+        return einops.rearrange(img, "c h w -> h w c")
+
+    images = data["images"]
+    images_dict = {name: convert_image(img) for name, img in images.items()}
+
+    data["images"] = images_dict
+    data["state"] = state
+    return data
+
+
+def _decode_state(state: np.ndarray, *, adapt_to_pi: bool = False) -> np.ndarray:
+    if adapt_to_pi:
+        # Flip the joints.
+        state = _joint_flip_mask() * state
+        # Reverse the gripper transformation that is being applied by the Aloha runtime.
+        state[[6, 13]] = _gripper_to_angular(state[[6, 13]])
+    return state
+
+
+def _encode_actions(actions: np.ndarray, *, adapt_to_pi: bool = False) -> np.ndarray:
+    if adapt_to_pi:
+        # Flip the joints.
+        actions = _joint_flip_mask() * actions
+        actions[:, [6, 13]] = _gripper_from_angular(actions[:, [6, 13]])
+    return actions
+
+
+def _encode_actions_inv(actions: np.ndarray, *, adapt_to_pi: bool = False) -> np.ndarray:
+    if adapt_to_pi:
+        actions = _joint_flip_mask() * actions
+        actions[:, [6, 13]] = _gripper_from_angular_inv(actions[:, [6, 13]])
+    return actions
diff --git a/openpi_runtime/openpi/policies/droid_policy.py b/openpi_runtime/openpi/policies/droid_policy.py
new file mode 100644
index 0000000000000000000000000000000000000000..55bdb419dd552daa9dd2943638b91c7d580e26fc
--- /dev/null
+++ b/openpi_runtime/openpi/policies/droid_policy.py
@@ -0,0 +1,81 @@
+import dataclasses
+
+import einops
+import numpy as np
+
+from openpi import transforms
+from openpi.models import model as _model
+
+
+def make_droid_example() -> dict:
+    """Creates a random input example for the Droid policy."""
+    return {
+        "observation/exterior_image_1_left": np.random.randint(256, size=(224, 224, 3), dtype=np.uint8),
+        "observation/wrist_image_left": np.random.randint(256, size=(224, 224, 3), dtype=np.uint8),
+        "observation/joint_position": np.random.rand(7),
+        "observation/gripper_position": np.random.rand(1),
+        "prompt": "do something",
+    }
+
+
+def _parse_image(image) -> np.ndarray:
+    image = np.asarray(image)
+    if np.issubdtype(image.dtype, np.floating):
+        image = (255 * image).astype(np.uint8)
+    if image.shape[0] == 3:
+        image = einops.rearrange(image, "c h w -> h w c")
+    return image
+
+
+@dataclasses.dataclass(frozen=True)
+class DroidInputs(transforms.DataTransformFn):
+    # Determines which model will be used.
+    model_type: _model.ModelType
+
+    def __call__(self, data: dict) -> dict:
+        gripper_pos = np.asarray(data["observation/gripper_position"])
+        if gripper_pos.ndim == 0:
+            # Ensure gripper position is a 1D array, not a scalar, so we can concatenate with joint positions
+            gripper_pos = gripper_pos[np.newaxis]
+        state = np.concatenate([data["observation/joint_position"], gripper_pos])
+
+        # Possibly need to parse images to uint8 (H,W,C) since LeRobot automatically
+        # stores as float32 (C,H,W), gets skipped for policy inference
+        base_image = _parse_image(data["observation/exterior_image_1_left"])
+        wrist_image = _parse_image(data["observation/wrist_image_left"])
+
+        match self.model_type:
+            case _model.ModelType.PI0 | _model.ModelType.PI05:
+                names = ("base_0_rgb", "left_wrist_0_rgb", "right_wrist_0_rgb")
+                images = (base_image, wrist_image, np.zeros_like(base_image))
+                image_masks = (np.True_, np.True_, np.False_)
+            case _model.ModelType.PI0_FAST:
+                names = ("base_0_rgb", "base_1_rgb", "wrist_0_rgb")
+                # We don't mask out padding images for FAST models.
+                images = (base_image, np.zeros_like(base_image), wrist_image)
+                image_masks = (np.True_, np.True_, np.True_)
+            case _:
+                raise ValueError(f"Unsupported model type: {self.model_type}")
+
+        inputs = {
+            "state": state,
+            "image": dict(zip(names, images, strict=True)),
+            "image_mask": dict(zip(names, image_masks, strict=True)),
+        }
+
+        if "actions" in data:
+            inputs["actions"] = np.asarray(data["actions"])
+
+        if "prompt" in data:
+            if isinstance(data["prompt"], bytes):
+                data["prompt"] = data["prompt"].decode("utf-8")
+            inputs["prompt"] = data["prompt"]
+
+        return inputs
+
+
+@dataclasses.dataclass(frozen=True)
+class DroidOutputs(transforms.DataTransformFn):
+    def __call__(self, data: dict) -> dict:
+        # Only return the first 8 dims.
+        return {"actions": np.asarray(data["actions"][..., :8])}
diff --git a/openpi_runtime/openpi/policies/libero_policy.py b/openpi_runtime/openpi/policies/libero_policy.py
new file mode 100644
index 0000000000000000000000000000000000000000..fe5aab0add5795531913363d7c46d916c81d1f9b
--- /dev/null
+++ b/openpi_runtime/openpi/policies/libero_policy.py
@@ -0,0 +1,100 @@
+import dataclasses
+
+import einops
+import numpy as np
+
+from openpi import transforms
+from openpi.models import model as _model
+
+
+def make_libero_example() -> dict:
+    """Creates a random input example for the Libero policy."""
+    return {
+        "observation/state": np.random.rand(8),
+        "observation/image": np.random.randint(256, size=(224, 224, 3), dtype=np.uint8),
+        "observation/wrist_image": np.random.randint(256, size=(224, 224, 3), dtype=np.uint8),
+        "prompt": "do something",
+    }
+
+
+def _parse_image(image) -> np.ndarray:
+    image = np.asarray(image)
+    if np.issubdtype(image.dtype, np.floating):
+        image = (255 * image).astype(np.uint8)
+    if image.shape[0] == 3:
+        image = einops.rearrange(image, "c h w -> h w c")
+    return image
+
+
+@dataclasses.dataclass(frozen=True)
+class LiberoInputs(transforms.DataTransformFn):
+    """
+    This class is used to convert inputs to the model to the expected format. It is used for both training and inference.
+
+    For your own dataset, you can copy this class and modify the keys based on the comments below to pipe
+    the correct elements of your dataset into the model.
+    """
+
+    # Determines which model will be used.
+    # Do not change this for your own dataset.
+    model_type: _model.ModelType
+
+    def __call__(self, data: dict) -> dict:
+        # Possibly need to parse images to uint8 (H,W,C) since LeRobot automatically
+        # stores as float32 (C,H,W), gets skipped for policy inference.
+        # Keep this for your own dataset, but if your dataset stores the images
+        # in a different key than "observation/image" or "observation/wrist_image",
+        # you should change it below.
+        # Pi0 models support three image inputs at the moment: one third-person view,
+        # and two wrist views (left and right). If your dataset does not have a particular type
+        # of image, e.g. wrist images, you can comment it out here and replace it with zeros like we do for the
+        # right wrist image below.
+        base_image = _parse_image(data["observation/image"])
+        wrist_image = _parse_image(data["observation/wrist_image"])
+
+        # Create inputs dict. Do not change the keys in the dict below.
+        inputs = {
+            "state": data["observation/state"],
+            "image": {
+                "base_0_rgb": base_image,
+                "left_wrist_0_rgb": wrist_image,
+                # Pad any non-existent images with zero-arrays of the appropriate shape.
+                "right_wrist_0_rgb": np.zeros_like(base_image),
+            },
+            "image_mask": {
+                "base_0_rgb": np.True_,
+                "left_wrist_0_rgb": np.True_,
+                # We only mask padding images for pi0 model, not pi0-FAST. Do not change this for your own dataset.
+                "right_wrist_0_rgb": np.True_ if self.model_type == _model.ModelType.PI0_FAST else np.False_,
+            },
+        }
+
+        # Pad actions to the model action dimension. Keep this for your own dataset.
+        # Actions are only available during training.
+        if "actions" in data:
+            inputs["actions"] = data["actions"]
+
+        # Pass the prompt (aka language instruction) to the model.
+        # Keep this for your own dataset (but modify the key if the instruction is not
+        # stored in "prompt"; the output dict always needs to have the key "prompt").
+        if "prompt" in data:
+            inputs["prompt"] = data["prompt"]
+
+        return inputs
+
+
+@dataclasses.dataclass(frozen=True)
+class LiberoOutputs(transforms.DataTransformFn):
+    """
+    This class is used to convert outputs from the model back the the dataset specific format. It is
+    used for inference only.
+
+    For your own dataset, you can copy this class and modify the action dimension based on the comments below.
+    """
+
+    def __call__(self, data: dict) -> dict:
+        # Only return the first N actions -- since we padded actions above to fit the model action
+        # dimension, we need to now parse out the correct number of actions in the return dict.
+        # For Libero, we only return the first 7 actions (since the rest is padding).
+        # For your own dataset, replace `7` with the action dimension of your dataset.
+        return {"actions": np.asarray(data["actions"][..., :7])}
diff --git a/openpi_runtime/openpi/policies/policy.py b/openpi_runtime/openpi/policies/policy.py
new file mode 100644
index 0000000000000000000000000000000000000000..b9b708bdcaffa086be4b22b84a29b8cc00c710e4
--- /dev/null
+++ b/openpi_runtime/openpi/policies/policy.py
@@ -0,0 +1,135 @@
+from collections.abc import Sequence
+import logging
+import pathlib
+import time
+from typing import Any, TypeAlias
+
+import flax
+import flax.traverse_util
+import jax
+import jax.numpy as jnp
+import numpy as np
+from openpi_client import base_policy as _base_policy
+import torch
+from typing_extensions import override
+
+from openpi import transforms as _transforms
+from openpi.models import model as _model
+from openpi.shared import array_typing as at
+from openpi.shared import nnx_utils
+
+BasePolicy: TypeAlias = _base_policy.BasePolicy
+
+
+class Policy(BasePolicy):
+    def __init__(
+        self,
+        model: _model.BaseModel,
+        *,
+        rng: at.KeyArrayLike | None = None,
+        transforms: Sequence[_transforms.DataTransformFn] = (),
+        output_transforms: Sequence[_transforms.DataTransformFn] = (),
+        sample_kwargs: dict[str, Any] | None = None,
+        metadata: dict[str, Any] | None = None,
+        pytorch_device: str = "cpu",
+        is_pytorch: bool = False,
+    ):
+        """Initialize the Policy.
+
+        Args:
+            model: The model to use for action sampling.
+            rng: Random number generator key for JAX models. Ignored for PyTorch models.
+            transforms: Input data transformations to apply before inference.
+            output_transforms: Output data transformations to apply after inference.
+            sample_kwargs: Additional keyword arguments to pass to model.sample_actions.
+            metadata: Additional metadata to store with the policy.
+            pytorch_device: Device to use for PyTorch models (e.g., "cpu", "cuda:0").
+                          Only relevant when is_pytorch=True.
+            is_pytorch: Whether the model is a PyTorch model. If False, assumes JAX model.
+        """
+        self._model = model
+        self._input_transform = _transforms.compose(transforms)
+        self._output_transform = _transforms.compose(output_transforms)
+        self._sample_kwargs = sample_kwargs or {}
+        self._metadata = metadata or {}
+        self._is_pytorch_model = is_pytorch
+        self._pytorch_device = pytorch_device
+
+        if self._is_pytorch_model:
+            self._model = self._model.to(pytorch_device)
+            self._model.eval()
+            self._sample_actions = model.sample_actions
+        else:
+            # JAX model setup
+            self._sample_actions = nnx_utils.module_jit(model.sample_actions)
+            self._rng = rng or jax.random.key(0)
+
+    @override
+    def infer(self, obs: dict, *, noise: np.ndarray | None = None) -> dict:  # type: ignore[misc]
+        # Make a copy since transformations may modify the inputs in place.
+        inputs = jax.tree.map(lambda x: x, obs)
+        inputs = self._input_transform(inputs)
+        if not self._is_pytorch_model:
+            # Make a batch and convert to jax.Array.
+            inputs = jax.tree.map(lambda x: jnp.asarray(x)[np.newaxis, ...], inputs)
+            self._rng, sample_rng_or_pytorch_device = jax.random.split(self._rng)
+        else:
+            # Convert inputs to PyTorch tensors and move to correct device
+            inputs = jax.tree.map(lambda x: torch.from_numpy(np.array(x)).to(self._pytorch_device)[None, ...], inputs)
+            sample_rng_or_pytorch_device = self._pytorch_device
+
+        # Prepare kwargs for sample_actions
+        sample_kwargs = dict(self._sample_kwargs)
+        if noise is not None:
+            noise = torch.from_numpy(noise).to(self._pytorch_device) if self._is_pytorch_model else jnp.asarray(noise)
+
+            if noise.ndim == 2:  # If noise is (action_horizon, action_dim), add batch dimension
+                noise = noise[None, ...]  # Make it (1, action_horizon, action_dim)
+            sample_kwargs["noise"] = noise
+
+        observation = _model.Observation.from_dict(inputs)
+        start_time = time.monotonic()
+        outputs = {
+            "state": inputs["state"],
+            "actions": self._sample_actions(sample_rng_or_pytorch_device, observation, **sample_kwargs),
+        }
+        model_time = time.monotonic() - start_time
+        if self._is_pytorch_model:
+            outputs = jax.tree.map(lambda x: np.asarray(x[0, ...].detach().cpu()), outputs)
+        else:
+            outputs = jax.tree.map(lambda x: np.asarray(x[0, ...]), outputs)
+
+        outputs = self._output_transform(outputs)
+        outputs["policy_timing"] = {
+            "infer_ms": model_time * 1000,
+        }
+        return outputs
+
+    @property
+    def metadata(self) -> dict[str, Any]:
+        return self._metadata
+
+
+class PolicyRecorder(_base_policy.BasePolicy):
+    """Records the policy's behavior to disk."""
+
+    def __init__(self, policy: _base_policy.BasePolicy, record_dir: str):
+        self._policy = policy
+
+        logging.info(f"Dumping policy records to: {record_dir}")
+        self._record_dir = pathlib.Path(record_dir)
+        self._record_dir.mkdir(parents=True, exist_ok=True)
+        self._record_step = 0
+
+    @override
+    def infer(self, obs: dict) -> dict:  # type: ignore[misc]
+        results = self._policy.infer(obs)
+
+        data = {"inputs": obs, "outputs": results}
+        data = flax.traverse_util.flatten_dict(data, sep="/")
+
+        output_path = self._record_dir / f"step_{self._record_step}"
+        self._record_step += 1
+
+        np.save(output_path, np.asarray(data))
+        return results
diff --git a/openpi_runtime/openpi/policies/policy_config.py b/openpi_runtime/openpi/policies/policy_config.py
new file mode 100644
index 0000000000000000000000000000000000000000..6570df05ed068f297d48326990a1cd10ee68ac5a
--- /dev/null
+++ b/openpi_runtime/openpi/policies/policy_config.py
@@ -0,0 +1,94 @@
+import logging
+import os
+import pathlib
+from typing import Any
+
+import jax.numpy as jnp
+
+import openpi.models.model as _model
+import openpi.policies.policy as _policy
+import openpi.shared.download as download
+from openpi.training import checkpoints as _checkpoints
+from openpi.training import config as _config
+import openpi.transforms as transforms
+
+
+def create_trained_policy(
+    train_config: _config.TrainConfig,
+    checkpoint_dir: pathlib.Path | str,
+    *,
+    repack_transforms: transforms.Group | None = None,
+    sample_kwargs: dict[str, Any] | None = None,
+    default_prompt: str | None = None,
+    norm_stats: dict[str, transforms.NormStats] | None = None,
+    pytorch_device: str | None = None,
+) -> _policy.Policy:
+    """Create a policy from a trained checkpoint.
+
+    Args:
+        train_config: The training config to use to create the model.
+        checkpoint_dir: The directory to load the model from.
+        repack_transforms: Optional transforms that will be applied before any other transforms.
+        sample_kwargs: The kwargs to pass to the `sample_actions` method. If not provided, the default
+            kwargs will be used.
+        default_prompt: The default prompt to use for the policy. Will inject the prompt into the input
+            data if it doesn't already exist.
+        norm_stats: The norm stats to use for the policy. If not provided, the norm stats will be loaded
+            from the checkpoint directory.
+        pytorch_device: Device to use for PyTorch models (e.g., "cpu", "cuda", "cuda:0").
+                      If None and is_pytorch=True, will use "cuda" if available, otherwise "cpu".
+
+    Note:
+        The function automatically detects whether the model is PyTorch-based by checking for the
+        presence of "model.safensors" in the checkpoint directory.
+    """
+    repack_transforms = repack_transforms or transforms.Group()
+    checkpoint_dir = download.maybe_download(str(checkpoint_dir))
+
+    # Check if this is a PyTorch model by looking for model.safetensors
+    weight_path = os.path.join(checkpoint_dir, "model.safetensors")
+    is_pytorch = os.path.exists(weight_path)
+
+    logging.info("Loading model...")
+    if is_pytorch:
+        model = train_config.model.load_pytorch(train_config, weight_path)
+        model.paligemma_with_expert.to_bfloat16_for_selected_params("bfloat16")
+    else:
+        model = train_config.model.load(_model.restore_params(checkpoint_dir / "params", dtype=jnp.bfloat16))
+    data_config = train_config.data.create(train_config.assets_dirs, train_config.model)
+    if norm_stats is None:
+        # We are loading the norm stats from the checkpoint instead of the config assets dir to make sure
+        # that the policy is using the same normalization stats as the original training process.
+        if data_config.asset_id is None:
+            raise ValueError("Asset id is required to load norm stats.")
+        norm_stats = _checkpoints.load_norm_stats(checkpoint_dir / "assets", data_config.asset_id)
+
+    # Determine the device to use for PyTorch models
+    if is_pytorch and pytorch_device is None:
+        try:
+            import torch
+
+            pytorch_device = "cuda" if torch.cuda.is_available() else "cpu"
+        except ImportError:
+            pytorch_device = "cpu"
+
+    return _policy.Policy(
+        model,
+        transforms=[
+            *repack_transforms.inputs,
+            transforms.InjectDefaultPrompt(default_prompt),
+            *data_config.data_transforms.inputs,
+            transforms.Normalize(norm_stats, use_quantiles=data_config.use_quantile_norm),
+            *data_config.model_transforms.inputs,
+        ],
+        output_transforms=[
+            *data_config.model_transforms.outputs,
+            transforms.Unnormalize(norm_stats, use_quantiles=data_config.use_quantile_norm),
+            *data_config.data_transforms.outputs,
+            *repack_transforms.outputs,
+        ],
+        sample_kwargs=sample_kwargs,
+        metadata=train_config.policy_metadata,
+        is_pytorch=is_pytorch,
+        pytorch_device=pytorch_device if is_pytorch else None,
+    )
diff --git a/openpi_runtime/openpi/policies/ur_policy.py b/openpi_runtime/openpi/policies/ur_policy.py
new file mode 100644
index 0000000000000000000000000000000000000000..847d00aee4de79906b38e4717a6c9997941bc306
--- /dev/null
+++ b/openpi_runtime/openpi/policies/ur_policy.py
@@ -0,0 +1,56 @@
+import dataclasses
+
+import einops
+import numpy as np
+
+from openpi import transforms
+from openpi.models import model as _model
+
+
+def _parse_image(image: np.ndarray) -> np.ndarray:
+    image = np.asarray(image)
+    if np.issubdtype(image.dtype, np.floating):
+        image = (255 * image).astype(np.uint8)
+    if image.shape[0] == 3:
+        image = einops.rearrange(image, "c h w -> h w c")
+    return image
+
+
+@dataclasses.dataclass(frozen=True)
+class URInputs(transforms.DataTransformFn):
+    """Map UR TCP observations and delta actions to OpenPI model inputs."""
+
+    model_type: _model.ModelType
+
+    def __call__(self, data: dict) -> dict:
+        base_image = _parse_image(data["observation/image"])
+        wrist_image = _parse_image(data["observation/wrist_image"])
+
+        inputs = {
+            "state": np.asarray(data["observation/state"]),
+            "image": {
+                "base_0_rgb": base_image,
+                "left_wrist_0_rgb": wrist_image,
+                "right_wrist_0_rgb": np.zeros_like(base_image),
+            },
+            "image_mask": {
+                "base_0_rgb": np.True_,
+                "left_wrist_0_rgb": np.True_,
+                "right_wrist_0_rgb": np.True_
+                if self.model_type == _model.ModelType.PI0_FAST
+                else np.False_,
+            },
+        }
+        if "actions" in data:
+            inputs["actions"] = np.asarray(data["actions"])
+        if "prompt" in data:
+            inputs["prompt"] = data["prompt"]
+        return inputs
+
+
+@dataclasses.dataclass(frozen=True)
+class UROutputs(transforms.DataTransformFn):
+    """Return the six TCP delta dimensions and absolute gripper command."""
+
+    def __call__(self, data: dict) -> dict:
+        return {"actions": np.asarray(data["actions"])[..., :7]}
diff --git a/openpi_runtime/openpi/py.typed b/openpi_runtime/openpi/py.typed
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/openpi_runtime/openpi/serving/websocket_policy_server.py b/openpi_runtime/openpi/serving/websocket_policy_server.py
new file mode 100644
index 0000000000000000000000000000000000000000..bdefa98b879323aca449550bf1985ae877eddd83
--- /dev/null
+++ b/openpi_runtime/openpi/serving/websocket_policy_server.py
@@ -0,0 +1,90 @@
+import asyncio
+import http
+import logging
+import time
+import traceback
+
+from openpi_client import base_policy as _base_policy
+from openpi_client import msgpack_numpy
+import websockets.asyncio.server as _server
+import websockets.frames
+
+logger = logging.getLogger(__name__)
+
+
+class WebsocketPolicyServer:
+    """Serves a policy using the websocket protocol. See websocket_client_policy.py for a client implementation.
+
+    Currently only implements the `load` and `infer` methods.
+    """
+
+    def __init__(
+        self,
+        policy: _base_policy.BasePolicy,
+        host: str = "0.0.0.0",
+        port: int | None = None,
+        metadata: dict | None = None,
+    ) -> None:
+        self._policy = policy
+        self._host = host
+        self._port = port
+        self._metadata = metadata or {}
+        logging.getLogger("websockets.server").setLevel(logging.INFO)
+
+    def serve_forever(self) -> None:
+        asyncio.run(self.run())
+
+    async def run(self):
+        async with _server.serve(
+            self._handler,
+            self._host,
+            self._port,
+            compression=None,
+            max_size=None,
+            process_request=_health_check,
+        ) as server:
+            await server.serve_forever()
+
+    async def _handler(self, websocket: _server.ServerConnection):
+        logger.info(f"Connection from {websocket.remote_address} opened")
+        packer = msgpack_numpy.Packer()
+
+        await websocket.send(packer.pack(self._metadata))
+
+        prev_total_time = None
+        while True:
+            try:
+                start_time = time.monotonic()
+                obs = msgpack_numpy.unpackb(await websocket.recv())
+
+                infer_time = time.monotonic()
+                action = self._policy.infer(obs)
+                infer_time = time.monotonic() - infer_time
+
+                action["server_timing"] = {
+                    "infer_ms": infer_time * 1000,
+                }
+                if prev_total_time is not None:
+                    # We can only record the last total time since we also want to include the send time.
+                    action["server_timing"]["prev_total_ms"] = prev_total_time * 1000
+
+                await websocket.send(packer.pack(action))
+                prev_total_time = time.monotonic() - start_time
+
+            except websockets.ConnectionClosed:
+                logger.info(f"Connection from {websocket.remote_address} closed")
+                break
+            except Exception:
+                await websocket.send(traceback.format_exc())
+                await websocket.close(
+                    code=websockets.frames.CloseCode.INTERNAL_ERROR,
+                    reason="Internal server error. Traceback included in previous frame.",
+                )
+                raise
+
+
+def _health_check(connection: _server.ServerConnection, request: _server.Request) -> _server.Response | None:
+    if request.path == "/healthz":
+        return connection.respond(http.HTTPStatus.OK, "OK\n")
+    # Continue with the normal request handling.
+    return None
diff --git a/openpi_runtime/openpi/shared/__init__.py b/openpi_runtime/openpi/shared/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/openpi_runtime/openpi/shared/array_typing.py b/openpi_runtime/openpi/shared/array_typing.py
new file mode 100644
index 0000000000000000000000000000000000000000..569eafef1401d4a34b0289c0efb2125f71d21dfb
--- /dev/null
+++ b/openpi_runtime/openpi/shared/array_typing.py
@@ -0,0 +1,89 @@
+import contextlib
+import functools as ft
+import inspect
+from typing import TypeAlias, TypeVar, cast
+
+import beartype
+import jax
+import jax._src.tree_util as private_tree_util
+import jax.core
+from jaxtyping import ArrayLike
+from jaxtyping import Bool  # noqa: F401
+from jaxtyping import DTypeLike  # noqa: F401
+from jaxtyping import Float
+from jaxtyping import Int  # noqa: F401
+from jaxtyping import Key  # noqa: F401
+from jaxtyping import Num  # noqa: F401
+from jaxtyping import PyTree
+from jaxtyping import Real  # noqa: F401
+from jaxtyping import UInt8  # noqa: F401
+from jaxtyping import config
+from jaxtyping import jaxtyped
+import jaxtyping._decorator
+import torch
+
+# patch jaxtyping to handle https://github.com/patrick-kidger/jaxtyping/issues/277.
+# the problem is that custom PyTree nodes are sometimes initialized with arbitrary types (e.g., `jax.ShapeDtypeStruct`,
+# `jax.Sharding`, or even <object>) due to JAX tracing operations. this patch skips typechecking when the stack trace
+# contains `jax._src.tree_util`, which should only be the case during tree unflattening.
+_original_check_dataclass_annotations = jaxtyping._decorator._check_dataclass_annotations  # noqa: SLF001
+# Redefine Array to include both JAX arrays and PyTorch tensors
+Array = jax.Array | torch.Tensor
+
+
+def _check_dataclass_annotations(self, typechecker):
+    if not any(
+        frame.frame.f_globals.get("__name__") in {"jax._src.tree_util", "flax.nnx.transforms.compilation"}
+        for frame in inspect.stack()
+    ):
+        return _original_check_dataclass_annotations(self, typechecker)
+    return None
+
+
+jaxtyping._decorator._check_dataclass_annotations = _check_dataclass_annotations  # noqa: SLF001
+
+KeyArrayLike: TypeAlias = jax.typing.ArrayLike
+Params: TypeAlias = PyTree[Float[ArrayLike, "..."]]
+
+T = TypeVar("T")
+
+
+# runtime type-checking decorator
+def typecheck(t: T) -> T:
+    return cast(T, ft.partial(jaxtyped, typechecker=beartype.beartype)(t))
+
+
+@contextlib.contextmanager
+def disable_typechecking():
+    initial = config.jaxtyping_disable
+    config.update("jaxtyping_disable", True)  # noqa: FBT003
+    yield
+    config.update("jaxtyping_disable", initial)
+
+
+def check_pytree_equality(*, expected: PyTree, got: PyTree, check_shapes: bool = False, check_dtypes: bool = False):
+    """Checks that two PyTrees have the same structure and optionally checks shapes and dtypes. Creates a much nicer
+    error message than if `jax.tree.map` is naively used on PyTrees with different structures.
+    """
+
+    if errors := list(private_tree_util.equality_errors(expected, got)):
+        raise ValueError(
+            "PyTrees have different structure:\n"
+            + (
+                "\n".join(
+                    f"   - at keypath '{jax.tree_util.keystr(path)}': expected {thing1}, got {thing2}, so {explanation}.\n"
+                    for path, thing1, thing2, explanation in errors
+                )
+            )
+        )
+
+    if check_shapes or check_dtypes:
+
+        def check(kp, x, y):
+            if check_shapes and x.shape != y.shape:
+                raise ValueError(f"Shape mismatch at {jax.tree_util.keystr(kp)}: expected {x.shape}, got {y.shape}")
+
+            if check_dtypes and x.dtype != y.dtype:
+                raise ValueError(f"Dtype mismatch at {jax.tree_util.keystr(kp)}: expected {x.dtype}, got {y.dtype}")
+
+        jax.tree_util.tree_map_with_path(check, expected, got)
diff --git a/openpi_runtime/openpi/shared/download.py b/openpi_runtime/openpi/shared/download.py
new file mode 100644
index 0000000000000000000000000000000000000000..582f8392df2a337fdba79f6f20babdb6fa76a321
--- /dev/null
+++ b/openpi_runtime/openpi/shared/download.py
@@ -0,0 +1,216 @@
+import concurrent.futures
+import datetime
+import logging
+import os
+import pathlib
+import re
+import shutil
+import stat
+import subprocess
+import time
+import urllib.parse
+
+import filelock
+import fsspec
+import fsspec.generic
+import tqdm_loggable.auto as tqdm
+
+# Environment variable to control cache directory path, ~/.cache/openpi will be used by default.
+_OPENPI_DATA_HOME = "OPENPI_DATA_HOME"
+DEFAULT_CACHE_DIR = "~/.cache/openpi"
+
+logger = logging.getLogger(__name__)
+
+
+def get_cache_dir() -> pathlib.Path:
+    cache_dir = pathlib.Path(os.getenv(_OPENPI_DATA_HOME, DEFAULT_CACHE_DIR)).expanduser().resolve()
+    cache_dir.mkdir(parents=True, exist_ok=True)
+    _set_folder_permission(cache_dir)
+    return cache_dir
+
+
+def maybe_download(url: str, *, force_download: bool = False, **kwargs) -> pathlib.Path:
+    """Download a file or directory from a remote filesystem to the local cache, and return the local path.
+
+    If the local file already exists, it will be returned directly.
+
+    It is safe to call this function concurrently from multiple processes.
+    See `get_cache_dir` for more details on the cache directory.
+
+    Args:
+        url: URL to the file to download.
+        force_download: If True, the file will be downloaded even if it already exists in the cache.
+        **kwargs: Additional arguments to pass to fsspec.
+
+    Returns:
+        Local path to the downloaded file or directory. That path is guaranteed to exist and is absolute.
+    """
+    # Don't use fsspec to parse the url to avoid unnecessary connection to the remote filesystem.
+    parsed = urllib.parse.urlparse(url)
+
+    # Short circuit if this is a local path.
+    if parsed.scheme == "":
+        path = pathlib.Path(url)
+        if not path.exists():
+            raise FileNotFoundError(f"File not found at {url}")
+        return path.resolve()
+
+    cache_dir = get_cache_dir()
+
+    local_path = cache_dir / parsed.netloc / parsed.path.strip("/")
+    local_path = local_path.resolve()
+
+    # Check if the cache should be invalidated.
+    invalidate_cache = False
+    if local_path.exists():
+        if force_download or _should_invalidate_cache(cache_dir, local_path):
+            invalidate_cache = True
+        else:
+            return local_path
+
+    try:
+        lock_path = local_path.with_suffix(".lock")
+        with filelock.FileLock(lock_path):
+            # Ensure consistent permissions for the lock file.
+            _ensure_permissions(lock_path)
+            # First, remove the existing cache if it is expired.
+            if invalidate_cache:
+                logger.info(f"Removing expired cached entry: {local_path}")
+                if local_path.is_dir():
+                    shutil.rmtree(local_path)
+                else:
+                    local_path.unlink()
+
+            if not local_path.exists():
+                # Download the data to a local cache.
+                logger.info(f"Downloading {url} to {local_path}")
+                scratch_path = local_path.with_suffix(".partial")
+                # Route openpi-assets through gsutil to avoid gcsfs auth issues with this bucket.
+                # All other gs:// URLs (e.g. big_vision) continue to use gcsfs as normal.
+                if parsed.scheme == "gs" and parsed.netloc == "openpi-assets":
+                    _download_gsutil(url, scratch_path, **kwargs)
+                else:
+                    _download_fsspec(url, scratch_path, **kwargs)
+
+                shutil.move(scratch_path, local_path)
+                _ensure_permissions(local_path)
+
+    except PermissionError as e:
+        msg = (
+            f"Local file permission error was encountered while downloading {url}. "
+            f"Please try again after removing the cached data using: `rm -rf {local_path}*`"
+        )
+        raise PermissionError(msg) from e
+
+    return local_path
+
+
+def _download_gsutil(url: str, local_path: pathlib.Path, **kwargs) -> None:
+    """Download a file or directory from GCS using gsutil if available, otherwise fall back to gcsfs."""
+    if shutil.which("gsutil") is None:
+        logger.warning(
+            "gsutil not found, falling back to gcsfs. This may fail if GCP credentials are not configured correctly."
+        )
+        _download_fsspec(url, local_path, **kwargs)
+        return
+    local_path.mkdir(parents=True, exist_ok=True)
+    subprocess.run(
+        ["gsutil", "-m", "cp", "-r", f"{url}/*", str(local_path)],
+        check=True,
+    )
+
+
+def _download_fsspec(url: str, local_path: pathlib.Path, **kwargs) -> None:
+    """Download a file from a remote filesystem to the local cache, and return the local path."""
+    fs, _ = fsspec.core.url_to_fs(url, **kwargs)
+    info = fs.info(url)
+    # Folders are represented by 0-byte objects with a trailing forward slash.
+    if is_dir := (info["type"] == "directory" or (info["size"] == 0 and info["name"].endswith("/"))):
+        total_size = fs.du(url)
+    else:
+        total_size = info["size"]
+    with tqdm.tqdm(total=total_size, unit="iB", unit_scale=True, unit_divisor=1024) as pbar:
+        executor = concurrent.futures.ThreadPoolExecutor(max_workers=1)
+        future = executor.submit(fs.get, url, local_path, recursive=is_dir)
+        while not future.done():
+            current_size = sum(f.stat().st_size for f in [*local_path.rglob("*"), local_path] if f.is_file())
+            pbar.update(current_size - pbar.n)
+            time.sleep(1)
+        pbar.update(total_size - pbar.n)
+
+
+def _set_permission(path: pathlib.Path, target_permission: int):
+    """chmod requires executable permission to be set, so we skip if the permission is already match with the target."""
+    if path.stat().st_mode & target_permission == target_permission:
+        logger.debug(f"Skipping {path} because it already has correct permissions")
+        return
+    path.chmod(target_permission)
+    logger.debug(f"Set {path} to {target_permission}")
+
+
+def _set_folder_permission(folder_path: pathlib.Path) -> None:
+    """Set folder permission to be read, write and searchable."""
+    _set_permission(folder_path, stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO)
+
+
+def _ensure_permissions(path: pathlib.Path) -> None:
+    """Since we are sharing cache directory with containerized runtime as well as training script, we need to
+    ensure that the cache directory has the correct permissions.
+    """
+
+    def _setup_folder_permission_between_cache_dir_and_path(path: pathlib.Path) -> None:
+        cache_dir = get_cache_dir()
+        relative_path = path.relative_to(cache_dir)
+        moving_path = cache_dir
+        for part in relative_path.parts:
+            _set_folder_permission(moving_path / part)
+            moving_path = moving_path / part
+
+    def _set_file_permission(file_path: pathlib.Path) -> None:
+        """Set all files to be read & writable, if it is a script, keep it as a script."""
+        file_rw = stat.S_IRUSR | stat.S_IWUSR | stat.S_IRGRP | stat.S_IWGRP | stat.S_IROTH | stat.S_IWOTH
+        if file_path.stat().st_mode & 0o100:
+            _set_permission(file_path, file_rw | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH)
+        else:
+            _set_permission(file_path, file_rw)
+
+    _setup_folder_permission_between_cache_dir_and_path(path)
+    for root, dirs, files in os.walk(str(path)):
+        root_path = pathlib.Path(root)
+        for file in files:
+            file_path = root_path / file
+            _set_file_permission(file_path)
+
+        for dir in dirs:
+            dir_path = root_path / dir
+            _set_folder_permission(dir_path)
+
+
+def _get_mtime(year: int, month: int, day: int) -> float:
+    """Get the mtime of a given date at midnight UTC."""
+    date = datetime.datetime(year, month, day, tzinfo=datetime.UTC)
+    return time.mktime(date.timetuple())
+
+
+# Map of relative paths, defined as regular expressions, to expiration timestamps (mtime format).
+# Partial matching will be used from top to bottom and the first match will be chosen.
+# Cached entries will be retained only if they are newer than the expiration timestamp.
+_INVALIDATE_CACHE_DIRS: dict[re.Pattern, float] = {
+    re.compile("openpi-assets/checkpoints/pi0_aloha_pen_uncap"): _get_mtime(2025, 2, 17),
+    re.compile("openpi-assets/checkpoints/pi0_libero"): _get_mtime(2025, 2, 6),
+    re.compile("openpi-assets/checkpoints/"): _get_mtime(2025, 2, 3),
+}
+
+
+def _should_invalidate_cache(cache_dir: pathlib.Path, local_path: pathlib.Path) -> bool:
+    """Invalidate the cache if it is expired. Return True if the cache was invalidated."""
+
+    assert local_path.exists(), f"File not found at {local_path}"
+
+    relative_path = str(local_path.relative_to(cache_dir))
+    for pattern, expire_time in _INVALIDATE_CACHE_DIRS.items():
+        if pattern.match(relative_path):
+            # Remove if not newer than the expiration timestamp.
+            return local_path.stat().st_mtime <= expire_time
+
+    return False
diff --git a/openpi_runtime/openpi/shared/image_tools.py b/openpi_runtime/openpi/shared/image_tools.py
new file mode 100644
index 0000000000000000000000000000000000000000..8cde35352021de1e66b5856eb1a18bf2dff61ee7
--- /dev/null
+++ b/openpi_runtime/openpi/shared/image_tools.py
@@ -0,0 +1,126 @@
+import functools
+
+import jax
+import jax.numpy as jnp
+import torch
+import torch.nn.functional as F  # noqa: N812
+
+import openpi.shared.array_typing as at
+
+
+@functools.partial(jax.jit, static_argnums=(1, 2, 3))
+@at.typecheck
+def resize_with_pad(
+    images: at.UInt8[at.Array, "*b h w c"] | at.Float[at.Array, "*b h w c"],
+    height: int,
+    width: int,
+    method: jax.image.ResizeMethod = jax.image.ResizeMethod.LINEAR,
+) -> at.UInt8[at.Array, "*b {height} {width} c"] | at.Float[at.Array, "*b {height} {width} c"]:
+    """Replicates tf.image.resize_with_pad. Resizes an image to a target height and width without distortion
+    by padding with black. If the image is float32, it must be in the range [-1, 1].
+    """
+    has_batch_dim = images.ndim == 4
+    if not has_batch_dim:
+        images = images[None]  # type: ignore
+    cur_height, cur_width = images.shape[1:3]
+    ratio = max(cur_width / width, cur_height / height)
+    resized_height = int(cur_height / ratio)
+    resized_width = int(cur_width / ratio)
+    resized_images = jax.image.resize(
+        images, (images.shape[0], resized_height, resized_width, images.shape[3]), method=method
+    )
+    if images.dtype == jnp.uint8:
+        # round from float back to uint8
+        resized_images = jnp.round(resized_images).clip(0, 255).astype(jnp.uint8)
+    elif images.dtype == jnp.float32:
+        resized_images = resized_images.clip(-1.0, 1.0)
+    else:
+        raise ValueError(f"Unsupported image dtype: {images.dtype}")
+
+    pad_h0, remainder_h = divmod(height - resized_height, 2)
+    pad_h1 = pad_h0 + remainder_h
+    pad_w0, remainder_w = divmod(width - resized_width, 2)
+    pad_w1 = pad_w0 + remainder_w
+    padded_images = jnp.pad(
+        resized_images,
+        ((0, 0), (pad_h0, pad_h1), (pad_w0, pad_w1), (0, 0)),
+        constant_values=0 if images.dtype == jnp.uint8 else -1.0,
+    )
+
+    if not has_batch_dim:
+        padded_images = padded_images[0]
+    return padded_images
+
+
+def resize_with_pad_torch(
+    images: torch.Tensor,
+    height: int,
+    width: int,
+    mode: str = "bilinear",
+) -> torch.Tensor:
+    """PyTorch version of resize_with_pad. Resizes an image to a target height and width without distortion
+    by padding with black. If the image is float32, it must be in the range [-1, 1].
+
+    Args:
+        images: Tensor of shape [*b, h, w, c] or [*b, c, h, w]
+        height: Target height
+        width: Target width
+        mode: Interpolation mode ('bilinear', 'nearest', etc.)
+
+    Returns:
+        Resized and padded tensor with same shape format as input
+    """
+    # Check if input is in channels-last format [*b, h, w, c] or channels-first [*b, c, h, w]
+    if images.shape[-1] <= 4:  # Assume channels-last format
+        channels_last = True
+        # Convert to channels-first for torch operations
+        if images.dim() == 3:
+            images = images.unsqueeze(0)  # Add batch dimension
+        images = images.permute(0, 3, 1, 2)  # [b, h, w, c] -> [b, c, h, w]
+    else:
+        channels_last = False
+        if images.dim() == 3:
+            images = images.unsqueeze(0)  # Add batch dimension
+
+    batch_size, channels, cur_height, cur_width = images.shape
+
+    # Calculate resize ratio
+    ratio = max(cur_width / width, cur_height / height)
+    resized_height = int(cur_height / ratio)
+    resized_width = int(cur_width / ratio)
+
+    # Resize
+    resized_images = F.interpolate(
+        images, size=(resized_height, resized_width), mode=mode, align_corners=False if mode == "bilinear" else None
+    )
+
+    # Handle dtype-specific clipping
+    if images.dtype == torch.uint8:
+        resized_images = torch.round(resized_images).clamp(0, 255).to(torch.uint8)
+    elif images.dtype == torch.float32:
+        resized_images = resized_images.clamp(-1.0, 1.0)
+    else:
+        raise ValueError(f"Unsupported image dtype: {images.dtype}")
+
+    # Calculate padding
+    pad_h0, remainder_h = divmod(height - resized_height, 2)
+    pad_h1 = pad_h0 + remainder_h
+    pad_w0, remainder_w = divmod(width - resized_width, 2)
+    pad_w1 = pad_w0 + remainder_w
+
+    # Pad
+    constant_value = 0 if images.dtype == torch.uint8 else -1.0
+    padded_images = F.pad(
+        resized_images,
+        (pad_w0, pad_w1, pad_h0, pad_h1),  # left, right, top, bottom
+        mode="constant",
+        value=constant_value,
+    )
+
+    # Convert back to original format if needed
+    if channels_last:
+        padded_images = padded_images.permute(0, 2, 3, 1)  # [b, c, h, w] -> [b, h, w, c]
+        if batch_size == 1 and images.shape[0] == 1:
+            padded_images = padded_images.squeeze(0)  # Remove batch dimension if it was added
+
+    return padded_images
diff --git a/openpi_runtime/openpi/shared/nnx_utils.py b/openpi_runtime/openpi/shared/nnx_utils.py
new file mode 100644
index 0000000000000000000000000000000000000000..29df222bcbc0e815d0b6bec046a2893e3b2b18a5
--- /dev/null
+++ b/openpi_runtime/openpi/shared/nnx_utils.py
@@ -0,0 +1,69 @@
+from collections.abc import Callable
+import dataclasses
+import functools
+import inspect
+import re
+from typing import Any, ParamSpec, TypeVar
+
+import flax.nnx as nnx
+import jax
+
+P = ParamSpec("P")
+R = TypeVar("R")
+
+
+def module_jit(meth: Callable[P, R], *jit_args, **jit_kwargs) -> Callable[P, R]:
+    """A higher-order function to JIT-compile `nnx.Module` methods, freezing the module's state in the process.
+
+    Why not `nnx.jit`? For some reason, naively applying `nnx.jit` to `nnx.Module` methods, bound or unbound, uses much
+    more memory than necessary. I'm guessing it has something to do with the fact that it must keep track of module
+    mutations. Also, `nnx.jit` has some inherent overhead compared to a standard `jax.jit`, since every call must
+    traverse the NNX module graph. See https://github.com/google/flax/discussions/4224 for details.
+
+    `module_jit` is an alternative that avoids these issues by freezing the module's state. The function returned by
+    `module_jit` acts exactly like the original method, except that the state of the module is frozen to whatever it was
+    when `module_jit` was called. Mutations to the module within `meth` are still allowed, but they will be discarded
+    after the method call completes.
+    """
+    if not (inspect.ismethod(meth) and isinstance(meth.__self__, nnx.Module)):
+        raise ValueError("module_jit must only be used on bound methods of nnx.Modules.")
+
+    graphdef, state = nnx.split(meth.__self__)
+
+    def fun(state: nnx.State, *args: P.args, **kwargs: P.kwargs) -> R:
+        module = nnx.merge(graphdef, state)
+        return meth.__func__(module, *args, **kwargs)
+
+    jitted_fn = jax.jit(fun, *jit_args, **jit_kwargs)
+
+    @functools.wraps(meth)
+    def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
+        return jitted_fn(state, *args, **kwargs)
+
+    return wrapper
+
+
+@dataclasses.dataclass(frozen=True)
+class PathRegex:
+    """NNX Filter that matches paths using a regex.
+
+    By default, paths are joined with a `/` separator. This can be overridden by setting the `sep` argument.
+    """
+
+    pattern: str | re.Pattern
+    sep: str = "/"
+
+    def __post_init__(self):
+        if not isinstance(self.pattern, re.Pattern):
+            object.__setattr__(self, "pattern", re.compile(self.pattern))
+
+    def __call__(self, path: nnx.filterlib.PathParts, x: Any) -> bool:
+        joined_path = self.sep.join(str(x) for x in path)
+        assert isinstance(self.pattern, re.Pattern)
+        return self.pattern.fullmatch(joined_path) is not None
+
+
+def state_map(state: nnx.State, filter: nnx.filterlib.Filter, fn: Callable[[Any], Any]) -> nnx.State:
+    """Apply a function to the leaves of the state that match the filter."""
+    filtered_keys = set(state.filter(filter).flat_state())
+    return state.map(lambda k, v: fn(v) if k in filtered_keys else v)
diff --git a/openpi_runtime/openpi/shared/normalize.py b/openpi_runtime/openpi/shared/normalize.py
new file mode 100644
index 0000000000000000000000000000000000000000..5a75faecfbf4267329824b103e4cdd091d729840
--- /dev/null
+++ b/openpi_runtime/openpi/shared/normalize.py
@@ -0,0 +1,146 @@
+import json
+import pathlib
+
+import numpy as np
+import numpydantic
+import pydantic
+
+
+@pydantic.dataclasses.dataclass
+class NormStats:
+    mean: numpydantic.NDArray
+    std: numpydantic.NDArray
+    q01: numpydantic.NDArray | None = None  # 1st quantile
+    q99: numpydantic.NDArray | None = None  # 99th quantile
+
+
+class RunningStats:
+    """Compute running statistics of a batch of vectors."""
+
+    def __init__(self):
+        self._count = 0
+        self._mean = None
+        self._mean_of_squares = None
+        self._min = None
+        self._max = None
+        self._histograms = None
+        self._bin_edges = None
+        self._num_quantile_bins = 5000  # for computing quantiles on the fly
+
+    def update(self, batch: np.ndarray) -> None:
+        """
+        Update the running statistics with a batch of vectors.
+
+        Args:
+            vectors (np.ndarray): An array where all dimensions except the last are batch dimensions.
+        """
+        batch = batch.reshape(-1, batch.shape[-1])
+        num_elements, vector_length = batch.shape
+        if self._count == 0:
+            self._mean = np.mean(batch, axis=0)
+            self._mean_of_squares = np.mean(batch**2, axis=0)
+            self._min = np.min(batch, axis=0)
+            self._max = np.max(batch, axis=0)
+            self._histograms = [np.zeros(self._num_quantile_bins) for _ in range(vector_length)]
+            self._bin_edges = [
+                np.linspace(self._min[i] - 1e-10, self._max[i] + 1e-10, self._num_quantile_bins + 1)
+                for i in range(vector_length)
+            ]
+        else:
+            if vector_length != self._mean.size:
+                raise ValueError("The length of new vectors does not match the initialized vector length.")
+            new_max = np.max(batch, axis=0)
+            new_min = np.min(batch, axis=0)
+            max_changed = np.any(new_max > self._max)
+            min_changed = np.any(new_min < self._min)
+            self._max = np.maximum(self._max, new_max)
+            self._min = np.minimum(self._min, new_min)
+
+            if max_changed or min_changed:
+                self._adjust_histograms()
+
+        self._count += num_elements
+
+        batch_mean = np.mean(batch, axis=0)
+        batch_mean_of_squares = np.mean(batch**2, axis=0)
+
+        # Update running mean and mean of squares.
+        self._mean += (batch_mean - self._mean) * (num_elements / self._count)
+        self._mean_of_squares += (batch_mean_of_squares - self._mean_of_squares) * (num_elements / self._count)
+
+        self._update_histograms(batch)
+
+    def get_statistics(self) -> NormStats:
+        """
+        Compute and return the statistics of the vectors processed so far.
+
+        Returns:
+            dict: A dictionary containing the computed statistics.
+        """
+        if self._count < 2:
+            raise ValueError("Cannot compute statistics for less than 2 vectors.")
+
+        variance = self._mean_of_squares - self._mean**2
+        stddev = np.sqrt(np.maximum(0, variance))
+        q01, q99 = self._compute_quantiles([0.01, 0.99])
+        return NormStats(mean=self._mean, std=stddev, q01=q01, q99=q99)
+
+    def _adjust_histograms(self):
+        """Adjust histograms when min or max changes."""
+        for i in range(len(self._histograms)):
+            old_edges = self._bin_edges[i]
+            new_edges = np.linspace(self._min[i], self._max[i], self._num_quantile_bins + 1)
+
+            # Redistribute the existing histogram counts to the new bins
+            new_hist, _ = np.histogram(old_edges[:-1], bins=new_edges, weights=self._histograms[i])
+
+            self._histograms[i] = new_hist
+            self._bin_edges[i] = new_edges
+
+    def _update_histograms(self, batch: np.ndarray) -> None:
+        """Update histograms with new vectors."""
+        for i in range(batch.shape[1]):
+            hist, _ = np.histogram(batch[:, i], bins=self._bin_edges[i])
+            self._histograms[i] += hist
+
+    def _compute_quantiles(self, quantiles):
+        """Compute quantiles based on histograms."""
+        results = []
+        for q in quantiles:
+            target_count = q * self._count
+            q_values = []
+            for hist, edges in zip(self._histograms, self._bin_edges, strict=True):
+                cumsum = np.cumsum(hist)
+                idx = np.searchsorted(cumsum, target_count)
+                q_values.append(edges[idx])
+            results.append(np.array(q_values))
+        return results
+
+
+class _NormStatsDict(pydantic.BaseModel):
+    norm_stats: dict[str, NormStats]
+
+
+def serialize_json(norm_stats: dict[str, NormStats]) -> str:
+    """Serialize the running statistics to a JSON string."""
+    return _NormStatsDict(norm_stats=norm_stats).model_dump_json(indent=2)
+
+
+def deserialize_json(data: str) -> dict[str, NormStats]:
+    """Deserialize the running statistics from a JSON string."""
+    return _NormStatsDict(**json.loads(data)).norm_stats
+
+
+def save(directory: pathlib.Path | str, norm_stats: dict[str, NormStats]) -> None:
+    """Save the normalization stats to a directory."""
+    path = pathlib.Path(directory) / "norm_stats.json"
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(serialize_json(norm_stats))
+
+
+def load(directory: pathlib.Path | str) -> dict[str, NormStats]:
+    """Load the normalization stats from a directory."""
+    path = pathlib.Path(directory) / "norm_stats.json"
+    if not path.exists():
+        raise FileNotFoundError(f"Norm stats file not found at: {path}")
+    return deserialize_json(path.read_text())
diff --git a/openpi_runtime/openpi/training/checkpoints.py b/openpi_runtime/openpi/training/checkpoints.py
new file mode 100644
index 0000000000000000000000000000000000000000..f32a8313979dffe39e831e2c9910d17677ba3c47
--- /dev/null
+++ b/openpi_runtime/openpi/training/checkpoints.py
@@ -0,0 +1,159 @@
+from __future__ import annotations
+
+import asyncio
+import concurrent.futures as futures
+import dataclasses
+import logging
+from typing import Protocol
+
+from etils import epath
+import jax
+import orbax.checkpoint as ocp
+import orbax.checkpoint.future as future
+
+from openpi.shared import array_typing as at
+import openpi.shared.normalize as _normalize
+import openpi.training.data_loader as _data_loader
+import openpi.training.utils as training_utils
+
+
+def initialize_checkpoint_dir(
+    checkpoint_dir: epath.Path | str, *, keep_period: int | None, overwrite: bool, resume: bool
+) -> tuple[ocp.CheckpointManager, bool]:
+    checkpoint_dir = epath.Path(checkpoint_dir).resolve()
+    resuming = False
+    if checkpoint_dir.exists():
+        if overwrite:
+            checkpoint_dir.rmtree()
+            checkpoint_dir.mkdir(parents=True, exist_ok=True)
+            logging.info(f"Wiped checkpoint directory {checkpoint_dir}")
+        elif resume:
+            resuming = True
+        else:
+            raise FileExistsError(
+                f"Checkpoint directory {checkpoint_dir} already exists. Use --overwrite or --resume "
+                "to indicate how to handle it."
+            )
+
+    checkpoint_dir.mkdir(parents=True, exist_ok=True)
+
+    mngr = ocp.CheckpointManager(
+        checkpoint_dir,
+        item_handlers={
+            "assets": CallbackHandler(),
+            "train_state": ocp.PyTreeCheckpointHandler(),
+            "params": ocp.PyTreeCheckpointHandler(),
+        },
+        options=ocp.CheckpointManagerOptions(
+            max_to_keep=1,
+            keep_period=keep_period,
+            create=False,
+            async_options=ocp.AsyncOptions(timeout_secs=7200),
+        ),
+    )
+
+    # Special case: the checkpoint directory exists and the user requests to resume training, but the training run did
+    # not get to the first checkpoint saved. In this case, we don't actually want the train script to try and restore a
+    # checkpoint, since it will fail.
+    if resuming and tuple(mngr.all_steps()) in [(), (0,)]:
+        logging.info("Checkpoint directory exists, but does not contain any checkpoints. Aborting resume.")
+        resuming = False
+
+    return mngr, resuming
+
+
+def save_state(
+    checkpoint_manager: ocp.CheckpointManager,
+    state: training_utils.TrainState,
+    data_loader: _data_loader.DataLoader,
+    step: int,
+):
+    def save_assets(directory: epath.Path):
+        # Save the normalization stats.
+        data_config = data_loader.data_config()
+        norm_stats = data_config.norm_stats
+        if norm_stats is not None and data_config.asset_id is not None:
+            _normalize.save(directory / data_config.asset_id, norm_stats)
+
+    # Split params that can be used for inference into a separate item.
+    with at.disable_typechecking():
+        train_state, params = _split_params(state)
+    items = {
+        "assets": save_assets,
+        "train_state": train_state,
+        "params": {"params": params},
+    }
+    checkpoint_manager.save(step, items)
+
+
+def restore_state(
+    checkpoint_manager: ocp.CheckpointManager,
+    state: training_utils.TrainState,
+    data_loader: _data_loader.DataLoader,
+    step: int | None = None,
+) -> training_utils.TrainState:
+    del data_loader
+
+    with at.disable_typechecking():
+        # Split params that can be used for inference into a separate item.
+        train_state, params = _split_params(state)
+        restored = checkpoint_manager.restore(
+            step,
+            items={
+                "train_state": train_state,
+                "params": {"params": params},
+            },
+        )
+    return _merge_params(restored["train_state"], restored["params"])
+
+
+def load_norm_stats(assets_dir: epath.Path | str, asset_id: str) -> dict[str, _normalize.NormStats] | None:
+    norm_stats_dir = epath.Path(assets_dir) / asset_id
+    norm_stats = _normalize.load(norm_stats_dir)
+    logging.info(f"Loaded norm stats from {norm_stats_dir}")
+    return norm_stats
+
+
+class Callback(Protocol):
+    def __call__(self, directory: epath.Path) -> None: ...
+
+
+class CallbackHandler(ocp.AsyncCheckpointHandler):
+    """A CheckpointHandler for calling an arbitrary function asynchronously. Only for saving, not for restoring."""
+
+    def save(self, directory: epath.Path, args: CallbackSave):
+        if jax.process_index() == 0:
+            args.callback(directory)
+
+    async def async_save(self, directory: epath.Path, args: CallbackSave) -> list[futures.Future]:
+        return [future.CommitFutureAwaitingContractedSignals(asyncio.to_thread(self.save, directory, args))]
+
+    def restore(self, *args, **kwargs):
+        raise NotImplementedError("CallbackHandler does not support restore")
+
+
+@ocp.args.register_with_handler(CallbackHandler, for_save=True)
+@dataclasses.dataclass
+class CallbackSave(ocp.args.CheckpointArgs):
+    callback: Callback
+
+
+@ocp.args.register_with_handler(CallbackHandler, for_restore=True)
+class CallbackRestore(ocp.args.CheckpointArgs): ...
+
+
+def _split_params(state: training_utils.TrainState) -> tuple[training_utils.TrainState, at.Params]:
+    if state.ema_params is not None:
+        params = state.ema_params
+        train_state = dataclasses.replace(state, ema_params=None)
+    else:
+        params = state.params
+        train_state = dataclasses.replace(state, params={})
+    return train_state, params
+
+
+def _merge_params(train_state: training_utils.TrainState, params: dict[str, at.Params]) -> training_utils.TrainState:
+    # Revert the logic inside `_split_params`. Assumes that existence of `params` means that EMA params were used during the split.
+    if train_state.params:
+        return dataclasses.replace(train_state, ema_params=params["params"])
+    return dataclasses.replace(train_state, params=params["params"])
diff --git a/openpi_runtime/openpi/training/config.py b/openpi_runtime/openpi/training/config.py
new file mode 100644
index 0000000000000000000000000000000000000000..0c8d13c51f12a43f7f8039f2df8ef0be31a83cc9
--- /dev/null
+++ b/openpi_runtime/openpi/training/config.py
@@ -0,0 +1,1070 @@
+"""See _CONFIGS for the list of available configs."""
+
+import abc
+from collections.abc import Sequence
+import dataclasses
+import difflib
+import logging
+import pathlib
+from typing import Any, Literal, Protocol, TypeAlias
+
+import etils.epath as epath
+import flax.nnx as nnx
+from typing_extensions import override
+import tyro
+
+import openpi.models.model as _model
+import openpi.models.pi0_config as pi0_config
+import openpi.models.pi0_fast as pi0_fast
+import openpi.models.tokenizer as _tokenizer
+import openpi.policies.aloha_policy as aloha_policy
+import openpi.policies.droid_policy as droid_policy
+import openpi.policies.libero_policy as libero_policy
+import openpi.policies.ur_policy as ur_policy
+import openpi.shared.download as _download
+import openpi.shared.normalize as _normalize
+import openpi.training.droid_rlds_dataset as droid_rlds_dataset
+import openpi.training.misc.polaris_config as polaris_config
+import openpi.training.misc.roboarena_config as roboarena_config
+import openpi.training.optimizer as _optimizer
+import openpi.training.weight_loaders as weight_loaders
+import openpi.transforms as _transforms
+
+ModelType: TypeAlias = _model.ModelType
+# Work around a tyro issue with using nnx.filterlib.Filter directly.
+Filter: TypeAlias = nnx.filterlib.Filter
+
+
+@dataclasses.dataclass(frozen=True)
+class AssetsConfig:
+    """Determines the location of assets (e.g., norm stats) that will be used to set up the data pipeline.
+
+    These assets will be replicated inside the checkpoint under the `assets/asset_id` directory.
+
+    This can be used to load assets from a different checkpoint (e.g., base model checkpoint) or some other
+    centralized location. For example, to load the norm stats for the Trossen robot from the base model checkpoint
+    during fine-tuning, use:
+
+    ```
+    AssetsConfig(
+        assets_dir="gs://openpi-assets/checkpoints/pi0_base/assets",
+        asset_id="trossen",
+    )
+    ```
+    """
+
+    # Assets directory. If not provided, the config assets_dirs will be used. This is useful to load assets from
+    # a different checkpoint (e.g., base model checkpoint) or some other centralized location.
+    assets_dir: str | None = None
+
+    # Asset id. If not provided, the repo id will be used. This allows users to reference assets that describe
+    # different robot platforms.
+    asset_id: str | None = None
+
+
+@dataclasses.dataclass(frozen=True)
+class DataConfig:
+    # LeRobot repo id. If None, fake data will be created.
+    repo_id: str | None = None
+    # Directory within the assets directory containing the data assets.
+    asset_id: str | None = None
+    # Contains precomputed normalization stats. If None, normalization will not be performed.
+    norm_stats: dict[str, _transforms.NormStats] | None = None
+
+    # Used to adopt the inputs from a dataset specific format to a common format
+    # which is expected by the data transforms.
+    repack_transforms: _transforms.Group = dataclasses.field(default_factory=_transforms.Group)
+    # Data transforms, typically include robot specific transformations. Will be applied
+    # before the data is normalized. See `model.Observation` and `model.Actions` to learn about the
+    # normalized data.
+    data_transforms: _transforms.Group = dataclasses.field(default_factory=_transforms.Group)
+    # Model specific transforms. Will be applied after the data is normalized.
+    model_transforms: _transforms.Group = dataclasses.field(default_factory=_transforms.Group)
+    # If true, will use quantile normalization. Otherwise, normal z-score normalization will be used.
+    use_quantile_norm: bool = False
+
+    # Names of keys that will be used by the data loader to generate the action sequence. The length of the
+    # sequence is defined by the `action_horizon` field in the model config. This should be adjusted if your
+    # LeRobot dataset is using different keys to represent the action.
+    action_sequence_keys: Sequence[str] = ("actions",)
+
+    # If true, will use the LeRobot dataset task to define the prompt.
+    prompt_from_task: bool = False
+
+    # Only used for RLDS data loader (ie currently only used for DROID).
+    rlds_data_dir: str | None = None
+    # Action space for DROID dataset.
+    action_space: droid_rlds_dataset.DroidActionSpace | None = None
+    # List of datasets to sample from: name, version, weight, and optionally filter_dict_path
+    datasets: Sequence[droid_rlds_dataset.RLDSDataset] = ()
+
+
+class GroupFactory(Protocol):
+    def __call__(self, model_config: _model.BaseModelConfig) -> _transforms.Group:
+        """Create a group."""
+
+
+@dataclasses.dataclass(frozen=True)
+class ModelTransformFactory(GroupFactory):
+    """Creates model transforms for standard pi0 models."""
+
+    # If provided, will determine the default prompt that be used by the model.
+    default_prompt: str | None = None
+
+    def __call__(self, model_config: _model.BaseModelConfig) -> _transforms.Group:
+        match model_config.model_type:
+            case _model.ModelType.PI0:
+                return _transforms.Group(
+                    inputs=[
+                        _transforms.InjectDefaultPrompt(self.default_prompt),
+                        _transforms.ResizeImages(224, 224),
+                        _transforms.TokenizePrompt(
+                            _tokenizer.PaligemmaTokenizer(model_config.max_token_len),
+                        ),
+                        _transforms.PadStatesAndActions(model_config.action_dim),
+                    ],
+                )
+            case _model.ModelType.PI05:
+                assert isinstance(model_config, pi0_config.Pi0Config)
+                return _transforms.Group(
+                    inputs=[
+                        _transforms.InjectDefaultPrompt(self.default_prompt),
+                        _transforms.ResizeImages(224, 224),
+                        _transforms.TokenizePrompt(
+                            _tokenizer.PaligemmaTokenizer(model_config.max_token_len),
+                            discrete_state_input=model_config.discrete_state_input,
+                        ),
+                        _transforms.PadStatesAndActions(model_config.action_dim),
+                    ],
+                )
+            case _model.ModelType.PI0_FAST:
+                tokenizer_cls = (
+                    _tokenizer.FASTTokenizer
+                    if model_config.fast_model_tokenizer is None
+                    else model_config.fast_model_tokenizer
+                )
+                tokenizer_kwargs = (
+                    {} if model_config.fast_model_tokenizer_kwargs is None else model_config.fast_model_tokenizer_kwargs
+                )
+                return _transforms.Group(
+                    inputs=[
+                        _transforms.InjectDefaultPrompt(self.default_prompt),
+                        _transforms.ResizeImages(224, 224),
+                        _transforms.TokenizeFASTInputs(
+                            tokenizer_cls(model_config.max_token_len, **tokenizer_kwargs),
+                        ),
+                    ],
+                    outputs=[
+                        _transforms.ExtractFASTActions(
+                            tokenizer_cls(model_config.max_token_len, **tokenizer_kwargs),
+                            action_horizon=model_config.action_horizon,
+                            action_dim=model_config.action_dim,
+                        )
+                    ],
+                )
+
+
+@dataclasses.dataclass(frozen=True)
+class DataConfigFactory(abc.ABC):
+    # The LeRobot repo id.
+    repo_id: str = tyro.MISSING
+    # Determines how the assets will be loaded.
+    assets: AssetsConfig = dataclasses.field(default_factory=AssetsConfig)
+    # Base config that will be updated by the factory.
+    base_config: tyro.conf.Suppress[DataConfig | None] = None
+
+    @abc.abstractmethod
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        """Create a data config."""
+
+    def create_base_config(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        repo_id = self.repo_id if self.repo_id is not tyro.MISSING else None
+        asset_id = self.assets.asset_id or repo_id
+        return dataclasses.replace(
+            self.base_config or DataConfig(),
+            repo_id=repo_id,
+            asset_id=asset_id,
+            norm_stats=self._load_norm_stats(epath.Path(self.assets.assets_dir or assets_dirs), asset_id),
+            use_quantile_norm=model_config.model_type != ModelType.PI0,
+        )
+
+    def _load_norm_stats(self, assets_dir: epath.Path, asset_id: str | None) -> dict[str, _transforms.NormStats] | None:
+        if asset_id is None:
+            return None
+        try:
+            data_assets_dir = str(assets_dir / asset_id)
+            norm_stats = _normalize.load(_download.maybe_download(data_assets_dir))
+            logging.info(f"Loaded norm stats from {data_assets_dir}")
+            return norm_stats
+        except FileNotFoundError:
+            logging.info(f"Norm stats not found in {data_assets_dir}, skipping.")
+        return None
+
+
+@dataclasses.dataclass(frozen=True)
+class FakeDataConfig(DataConfigFactory):
+    repo_id: str = "fake"
+
+    @override
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        return DataConfig(repo_id=self.repo_id)
+
+
+@dataclasses.dataclass(frozen=True)
+class SimpleDataConfig(DataConfigFactory):
+    # Factory for the data transforms.
+    data_transforms: tyro.conf.Suppress[GroupFactory] = dataclasses.field(default_factory=GroupFactory)
+    # Factory for the model transforms.
+    model_transforms: tyro.conf.Suppress[GroupFactory] = dataclasses.field(default_factory=ModelTransformFactory)
+
+    @override
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        return dataclasses.replace(
+            self.create_base_config(assets_dirs, model_config),
+            data_transforms=self.data_transforms(model_config),
+            model_transforms=self.model_transforms(model_config),
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class LeRobotAlohaDataConfig(DataConfigFactory):
+    # If true, will convert joint dimensions to deltas with respect to the current state before passing to the model.
+    # Gripper dimensions will remain in absolute values.
+    use_delta_joint_actions: bool = True
+    # If provided, will be injected into the input data if the "prompt" key is not present.
+    default_prompt: str | None = None
+    # If true, this will convert the joint and gripper values from the standard Aloha space to
+    # the space used by the pi internal runtime which was used to train the base model. People who
+    # use standard Aloha data should set this to true.
+    adapt_to_pi: bool = True
+
+    # Repack transforms.
+    repack_transforms: tyro.conf.Suppress[_transforms.Group] = dataclasses.field(
+        default=_transforms.Group(
+            inputs=[
+                _transforms.RepackTransform(
+                    {
+                        "images": {"cam_high": "observation.images.top"},
+                        "state": "observation.state",
+                        "actions": "action",
+                    }
+                )
+            ]
+        )
+    )
+    # Action keys that will be used to read the action sequence from the dataset.
+    action_sequence_keys: Sequence[str] = ("action",)
+
+    @override
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        data_transforms = _transforms.Group(
+            inputs=[aloha_policy.AlohaInputs(adapt_to_pi=self.adapt_to_pi)],
+            outputs=[aloha_policy.AlohaOutputs(adapt_to_pi=self.adapt_to_pi)],
+        )
+        if self.use_delta_joint_actions:
+            delta_action_mask = _transforms.make_bool_mask(6, -1, 6, -1)
+            data_transforms = data_transforms.push(
+                inputs=[_transforms.DeltaActions(delta_action_mask)],
+                outputs=[_transforms.AbsoluteActions(delta_action_mask)],
+            )
+
+        model_transforms = ModelTransformFactory(default_prompt=self.default_prompt)(model_config)
+
+        return dataclasses.replace(
+            self.create_base_config(assets_dirs, model_config),
+            repack_transforms=self.repack_transforms,
+            data_transforms=data_transforms,
+            model_transforms=model_transforms,
+            action_sequence_keys=self.action_sequence_keys,
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class LeRobotLiberoDataConfig(DataConfigFactory):
+    """
+    This config is used to configure transforms that are applied at various parts of the data pipeline.
+    For your own dataset, you can copy this class and modify the transforms to match your dataset based on the
+    comments below.
+    """
+
+    extra_delta_transform: bool = False
+
+    @override
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        # The repack transform is *only* applied to the data coming from the dataset,
+        # and *not* during inference. We can use it to make inputs from the dataset look
+        # as close as possible to those coming from the inference environment (e.g. match the keys).
+        # Below, we match the keys in the dataset (which we defined in the data conversion script) to
+        # the keys we use in our inference pipeline (defined in the inference script for libero).
+        # For your own dataset, first figure out what keys your environment passes to the policy server
+        # and then modify the mappings below so your dataset's keys get matched to those target keys.
+        # The repack transform simply remaps key names here.
+        repack_transform = _transforms.Group(
+            inputs=[
+                _transforms.RepackTransform(
+                    {
+                        "observation/image": "image",
+                        "observation/wrist_image": "wrist_image",
+                        "observation/state": "state",
+                        "actions": "actions",
+                        "prompt": "prompt",
+                    }
+                )
+            ]
+        )
+
+        # The data transforms are applied to the data coming from the dataset *and* during inference.
+        # Below, we define the transforms for data going into the model (``inputs``) and the transforms
+        # for data coming out of the model (``outputs``) (the latter is only used during inference).
+        # We defined these transforms in `libero_policy.py`. You can check the detailed comments there for
+        # how to modify the transforms to match your dataset. Once you created your own transforms, you can
+        # replace the transforms below with your own.
+        data_transforms = _transforms.Group(
+            inputs=[libero_policy.LiberoInputs(model_type=model_config.model_type)],
+            outputs=[libero_policy.LiberoOutputs()],
+        )
+
+        # One additional data transform: pi0 models are trained on delta actions (relative to the first
+        # state in each action chunk). IF your data has ``absolute`` actions (e.g. target joint angles)
+        # you can uncomment the following line to convert the actions to delta actions. The only exception
+        # is for the gripper actions which are always absolute.
+        # In the example below, we would apply the delta conversion to the first 6 actions (joints) and
+        # leave the 7th action (gripper) unchanged, i.e. absolute.
+        # In Libero, the raw actions in the dataset are already delta actions, so we *do not* need to
+        # apply a separate delta conversion (that's why it's commented out). Choose whether to apply this
+        # transform based on whether your dataset uses ``absolute`` or ``delta`` actions out of the box.
+
+        # LIBERO already represents actions as deltas, but we have some old Pi0 checkpoints that are trained with this
+        # extra delta transform.
+        if self.extra_delta_transform:
+            delta_action_mask = _transforms.make_bool_mask(6, -1)
+            data_transforms = data_transforms.push(
+                inputs=[_transforms.DeltaActions(delta_action_mask)],
+                outputs=[_transforms.AbsoluteActions(delta_action_mask)],
+            )
+
+        # Model transforms include things like tokenizing the prompt and action targets
+        # You do not need to change anything here for your own dataset.
+        model_transforms = ModelTransformFactory()(model_config)
+
+        # We return all data transforms for training and inference. No need to change anything here.
+        return dataclasses.replace(
+            self.create_base_config(assets_dirs, model_config),
+            repack_transforms=repack_transform,
+            data_transforms=data_transforms,
+            model_transforms=model_transforms,
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class LeRobotURDataConfig(DataConfigFactory):
+    """Data pipeline for keyboard-collected UR TCP delta trajectories."""
+
+    @override
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        repack_transform = _transforms.Group(
+            inputs=[
+                _transforms.RepackTransform(
+                    {
+                        "observation/image": "video.image_0",
+                        "observation/wrist_image": "video.wrist",
+                        "observation/state": "observation.state",
+                        "actions": "action",
+                        "prompt": "prompt",
+                    }
+                )
+            ]
+        )
+        data_transforms = _transforms.Group(
+            inputs=[ur_policy.URInputs(model_type=model_config.model_type)],
+            outputs=[ur_policy.UROutputs()],
+        )
+        model_transforms = ModelTransformFactory()(model_config)
+
+        return dataclasses.replace(
+            self.create_base_config(assets_dirs, model_config),
+            repack_transforms=repack_transform,
+            data_transforms=data_transforms,
+            model_transforms=model_transforms,
+            action_sequence_keys=("action",),
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class RLDSDroidDataConfig(DataConfigFactory):
+    """
+    Config for training on DROID, using RLDS data format (for efficient training on larger datasets).
+    """
+
+    rlds_data_dir: str | None = None
+    action_space: droid_rlds_dataset.DroidActionSpace | None = None
+
+    # Filtering options. Can pass a path to a dictionary that maps episodes to timestep ranges
+    # to tuples denoting ranges of time steps to keep (start, end). Episodes are uniquely identified with
+    # f"{recording_folderpath}--{file_path}", both of which are present in the RLDS episode metadata.
+
+    # List of datasets to sample from: name, version, weight, and optionally filter_dict_path
+    datasets: Sequence[droid_rlds_dataset.RLDSDataset] = (
+        droid_rlds_dataset.RLDSDataset(
+            name="droid",
+            version="1.0.1",
+            weight=1.0,
+            filter_dict_path="gs://openpi-assets/droid/droid_sample_ranges_v1_0_1.json",
+        ),
+    )
+
+    @override
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        repack_transform = _transforms.Group(
+            inputs=[
+                _transforms.RepackTransform(
+                    {
+                        "observation/exterior_image_1_left": "observation/image",
+                        "observation/wrist_image_left": "observation/wrist_image",
+                        "observation/joint_position": "observation/joint_position",
+                        "observation/gripper_position": "observation/gripper_position",
+                        "actions": "actions",
+                        "prompt": "prompt",
+                    }
+                )
+            ]
+        )
+
+        data_transforms = _transforms.Group(
+            inputs=[droid_policy.DroidInputs(model_type=model_config.model_type)],
+            outputs=[droid_policy.DroidOutputs()],
+        )
+
+        if self.action_space == droid_rlds_dataset.DroidActionSpace.JOINT_POSITION:
+            # Data loader returns absolute joint position actions -- convert to delta actions for training.
+            delta_action_mask = _transforms.make_bool_mask(7, -1)
+            data_transforms = data_transforms.push(
+                inputs=[_transforms.DeltaActions(delta_action_mask)],
+                outputs=[_transforms.AbsoluteActions(delta_action_mask)],
+            )
+
+        model_transforms = ModelTransformFactory()(model_config)
+
+        assert self.rlds_data_dir is not None, "Need to set rlds data dir for RLDS data loader."
+
+        return dataclasses.replace(
+            self.create_base_config(assets_dirs, model_config),
+            repack_transforms=repack_transform,
+            data_transforms=data_transforms,
+            model_transforms=model_transforms,
+            rlds_data_dir=self.rlds_data_dir,
+            action_space=self.action_space,
+            datasets=self.datasets,
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class LeRobotDROIDDataConfig(DataConfigFactory):
+    """
+    Example data config for custom DROID dataset in LeRobot format.
+    To convert your custom DROID dataset (<10s of hours) to LeRobot format, see examples/droid/convert_droid_data_to_lerobot.py
+    """
+
+    @override
+    def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig) -> DataConfig:
+        repack_transform = _transforms.Group(
+            inputs=[
+                _transforms.RepackTransform(
+                    {
+                        "observation/exterior_image_1_left": "exterior_image_1_left",
+                        "observation/exterior_image_2_left": "exterior_image_2_left",
+                        "observation/wrist_image_left": "wrist_image_left",
+                        "observation/joint_position": "joint_position",
+                        "observation/gripper_position": "gripper_position",
+                        "actions": "actions",
+                        "prompt": "prompt",
+                    }
+                )
+            ]
+        )
+        # We assume joint *velocity* actions, so we should *not* apply an additional delta transform.
+        data_transforms = _transforms.Group(
+            inputs=[droid_policy.DroidInputs(model_type=model_config.model_type)],
+            outputs=[droid_policy.DroidOutputs()],
+        )
+        model_transforms = ModelTransformFactory()(model_config)
+
+        return dataclasses.replace(
+            self.create_base_config(assets_dirs, model_config),
+            repack_transforms=repack_transform,
+            data_transforms=data_transforms,
+            model_transforms=model_transforms,
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class TrainConfig:
+    # Name of the config. Must be unique. Will be used to reference this config.
+    name: tyro.conf.Suppress[str]
+    # Project name.
+    project_name: str = "openpi"
+    # Experiment name. Will be used to name the metadata and checkpoint directories.
+    exp_name: str = tyro.MISSING
+
+    # Defines the model config. Some attributes (action_dim, action_horizon, and max_token_len) are shared by all models
+    # -- see BaseModelConfig. Specific model implementations (e.g., Pi0Config) inherit from BaseModelConfig and may
+    # define additional attributes.
+    model: _model.BaseModelConfig = dataclasses.field(default_factory=pi0_config.Pi0Config)
+
+    # A weight loader can optionally load (possibly partial) weights from disk after the model is initialized.
+    weight_loader: weight_loaders.WeightLoader = dataclasses.field(default_factory=weight_loaders.NoOpWeightLoader)
+
+    # Optional path to a PyTorch checkpoint to load weights from.
+    pytorch_weight_path: str | None = None
+
+    # Precision for PyTorch training.
+    pytorch_training_precision: Literal["bfloat16", "float32"] = "bfloat16"
+
+    lr_schedule: _optimizer.LRScheduleConfig = dataclasses.field(default_factory=_optimizer.CosineDecaySchedule)
+    optimizer: _optimizer.OptimizerConfig = dataclasses.field(default_factory=_optimizer.AdamW)
+    ema_decay: float | None = 0.99
+
+    # Specifies which weights should be frozen.
+    freeze_filter: tyro.conf.Suppress[Filter] = dataclasses.field(default_factory=nnx.Nothing)
+
+    # Determines the data to be trained on.
+    data: DataConfigFactory = dataclasses.field(default_factory=FakeDataConfig)
+
+    # Base directory for config assets (e.g., norm stats).
+    assets_base_dir: str = "./assets"
+    # Base directory for checkpoints.
+    checkpoint_base_dir: str = "./checkpoints"
+
+    # Random seed that will be used by random generators during training.
+    seed: int = 42
+    # Global batch size.
+    batch_size: int = 32
+    # Number of workers to use for the data loader. Increasing this number will speed up data loading but
+    # will increase memory and CPU usage.
+    num_workers: int = 2
+    # Number of train steps (batches) to run.
+    num_train_steps: int = 30_000
+
+    # How often (in steps) to log training metrics.
+    log_interval: int = 100
+    # How often (in steps) to save checkpoints.
+    save_interval: int = 1000
+    # If set, any existing checkpoints matching step % keep_period == 0 will not be deleted.
+    keep_period: int | None = 5000
+
+    # If true, will overwrite the checkpoint directory if it already exists.
+    overwrite: bool = False
+    # If true, will resume training from the last checkpoint.
+    resume: bool = False
+
+    # If true, will enable wandb logging.
+    wandb_enabled: bool = True
+
+    # Used to pass metadata to the policy server.
+    policy_metadata: dict[str, Any] | None = None
+
+    # If the value is greater than 1, FSDP will be enabled and shard across number of specified devices; overall
+    # device memory will be reduced but training could potentially be slower.
+    # eg. if total device is 4 and fsdp devices is 2; then the model will shard to 2 devices and run
+    # data parallel between 2 groups of devices.
+    fsdp_devices: int = 1
+
+    @property
+    def assets_dirs(self) -> pathlib.Path:
+        """Get the assets directory for this config."""
+        return (pathlib.Path(self.assets_base_dir) / self.name).resolve()
+
+    @property
+    def checkpoint_dir(self) -> pathlib.Path:
+        """Get the checkpoint directory for this config."""
+        if not self.exp_name:
+            raise ValueError("--exp_name must be set")
+        return (pathlib.Path(self.checkpoint_base_dir) / self.name / self.exp_name).resolve()
+
+    @property
+    def trainable_filter(self) -> nnx.filterlib.Filter:
+        """Get the filter for the trainable parameters."""
+        return nnx.All(nnx.Param, nnx.Not(self.freeze_filter))
+
+    def __post_init__(self) -> None:
+        if self.resume and self.overwrite:
+            raise ValueError("Cannot resume and overwrite at the same time.")
+
+
+# Use `get_config` if you need to get a config by name in your code.
+_CONFIGS = [
+    #
+    # Inference Aloha configs.
+    #
+    TrainConfig(
+        name="pi0_aloha",
+        model=pi0_config.Pi0Config(),
+        data=LeRobotAlohaDataConfig(
+            assets=AssetsConfig(asset_id="trossen"),
+        ),
+        policy_metadata={"reset_pose": [0, -1.5, 1.5, 0, 0, 0]},
+    ),
+    TrainConfig(
+        name="pi05_aloha",
+        model=pi0_config.Pi0Config(pi05=True),
+        data=LeRobotAlohaDataConfig(
+            assets=AssetsConfig(asset_id="trossen"),
+        ),
+        policy_metadata={"reset_pose": [0, -1.5, 1.5, 0, 0, 0]},
+    ),
+    TrainConfig(
+        name="pi0_aloha_towel",
+        model=pi0_config.Pi0Config(),
+        data=LeRobotAlohaDataConfig(
+            assets=AssetsConfig(asset_id="trossen"),
+            default_prompt="fold the towel",
+        ),
+        policy_metadata={"reset_pose": [0, -1.5, 1.5, 0, 0, 0]},
+    ),
+    TrainConfig(
+        name="pi0_aloha_tupperware",
+        model=pi0_config.Pi0Config(),
+        data=LeRobotAlohaDataConfig(
+            assets=AssetsConfig(asset_id="trossen"),
+            default_prompt="open the tupperware and put the food on the plate",
+        ),
+        policy_metadata={"reset_pose": [0, -1.5, 1.5, 0, 0, 0]},
+    ),
+    #
+    # Inference DROID configs.
+    #
+    TrainConfig(
+        name="pi0_droid",
+        model=pi0_config.Pi0Config(action_horizon=10),
+        data=SimpleDataConfig(
+            assets=AssetsConfig(asset_id="droid"),
+            data_transforms=lambda model: _transforms.Group(
+                inputs=[droid_policy.DroidInputs(model_type=ModelType.PI0)],
+                outputs=[droid_policy.DroidOutputs()],
+            ),
+            base_config=DataConfig(
+                prompt_from_task=True,
+            ),
+        ),
+    ),
+    TrainConfig(
+        name="pi0_fast_droid",
+        model=pi0_fast.Pi0FASTConfig(action_dim=8, action_horizon=10),
+        data=SimpleDataConfig(
+            assets=AssetsConfig(asset_id="droid"),
+            data_transforms=lambda model: _transforms.Group(
+                inputs=[droid_policy.DroidInputs(model_type=ModelType.PI0_FAST)],
+                outputs=[droid_policy.DroidOutputs()],
+            ),
+            base_config=DataConfig(
+                prompt_from_task=True,
+            ),
+        ),
+    ),
+    TrainConfig(
+        name="pi05_droid",
+        model=pi0_config.Pi0Config(action_horizon=15, pi05=True),
+        data=SimpleDataConfig(
+            assets=AssetsConfig(asset_id="droid"),
+            data_transforms=lambda model: _transforms.Group(
+                inputs=[droid_policy.DroidInputs(model_type=ModelType.PI05)],
+                outputs=[droid_policy.DroidOutputs()],
+            ),
+            base_config=DataConfig(
+                prompt_from_task=True,
+            ),
+        ),
+    ),
+    #
+    # Fine-tuning Libero configs.
+    #
+    # These train configs define the hyperparameters for fine-tuning the base model on your own dataset.
+    # They are used to define key elements like the dataset you are training on, the base checkpoint you
+    # are using, and other hyperparameters like how many training steps to run or what learning rate to use.
+    # For your own dataset, you can copy this class and modify the dataset name, and data transforms based on
+    # the comments below.
+    TrainConfig(
+        # Change the name to reflect your model and dataset.
+        name="pi0_libero",
+        # Here you define the model config -- In this example we use pi0 as the model
+        # architecture and perform *full* finetuning. in the examples below we show how to modify
+        # this to perform *low-memory* (LORA) finetuning and use pi0-FAST as an alternative architecture.
+        model=pi0_config.Pi0Config(),
+        # Here you define the dataset you are training on. In this example we use the Libero
+        # dataset. For your own dataset, you can change the repo_id to point to your dataset.
+        # Also modify the DataConfig to use the new config you made for your dataset above.
+        data=LeRobotLiberoDataConfig(
+            repo_id="physical-intelligence/libero",
+            base_config=DataConfig(
+                # This flag determines whether we load the prompt (i.e. the task instruction) from the
+                # ``task`` field in the LeRobot dataset. If set to True, the prompt will show up in
+                # a field called ``prompt`` in the input dict. The recommended setting is True.
+                prompt_from_task=True,
+            ),
+            extra_delta_transform=True,
+        ),
+        # Here you define which pre-trained checkpoint you want to load to initialize the model.
+        # This should match the model config you chose above -- i.e. in this case we use the pi0 base model.
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi0_base/params"),
+        # Below you can define other hyperparameters like the learning rate, number of training steps, etc.
+        # Check the base TrainConfig class for a full list of available hyperparameters.
+        num_train_steps=30_000,
+    ),
+    TrainConfig(
+        name="pi0_libero_low_mem_finetune",
+        # Here is an example of loading a pi0 model for LoRA fine-tuning.
+        model=pi0_config.Pi0Config(paligemma_variant="gemma_2b_lora", action_expert_variant="gemma_300m_lora"),
+        data=LeRobotLiberoDataConfig(
+            repo_id="physical-intelligence/libero",
+            base_config=DataConfig(prompt_from_task=True),
+            extra_delta_transform=True,
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi0_base/params"),
+        num_train_steps=30_000,
+        # The freeze filter defines which parameters should be frozen during training.
+        # We have a convenience function in the model config that returns the default freeze filter
+        # for the given model config for LoRA finetuning. Just make sure it matches the model config
+        # you chose above.
+        freeze_filter=pi0_config.Pi0Config(
+            paligemma_variant="gemma_2b_lora", action_expert_variant="gemma_300m_lora"
+        ).get_freeze_filter(),
+        # Turn off EMA for LoRA finetuning.
+        ema_decay=None,
+    ),
+    TrainConfig(
+        name="pi0_fast_libero",
+        # Here is an example of loading a pi0-FAST model for full finetuning.
+        # Modify action_dim and action_horizon to match your dataset (action horizon is equal to
+        # the desired action chunk length).
+        # The max_token_len is the maximum number of (non-image) tokens the model can handle.
+        # This includes the tokenized prompt, proprioceptive state, and (FAST-tokenized) action tokens.
+        # Choosing this value too small may chop off tokens at the end of your sequence (the code will throw
+        # a warning), while choosing it too large will waste memory (since we pad each batch element to the
+        # max_token_len). A good rule of thumb is to use approx 180 for single-arm robots, and approx 250 for
+        # two-arm robots. Generally, err on the lower side here first, and potentially increase the value if
+        # you see many warnings being thrown during training.
+        model=pi0_fast.Pi0FASTConfig(action_dim=7, action_horizon=10, max_token_len=180),
+        data=LeRobotLiberoDataConfig(
+            repo_id="physical-intelligence/libero",
+            base_config=DataConfig(prompt_from_task=True),
+            extra_delta_transform=True,
+        ),
+        # Note that we load the pi0-FAST base model checkpoint here.
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi0_fast_base/params"),
+        num_train_steps=30_000,
+    ),
+    TrainConfig(
+        name="pi0_fast_libero_low_mem_finetune",
+        # Here is an example of loading a pi0-FAST model for LoRA finetuning.
+        # For setting action_dim, action_horizon, and max_token_len, see the comments above.
+        model=pi0_fast.Pi0FASTConfig(
+            action_dim=7, action_horizon=10, max_token_len=180, paligemma_variant="gemma_2b_lora"
+        ),
+        data=LeRobotLiberoDataConfig(
+            repo_id="physical-intelligence/libero",
+            base_config=DataConfig(prompt_from_task=True),
+            extra_delta_transform=True,
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi0_fast_base/params"),
+        num_train_steps=30_000,
+        # Again, make sure to match the model config above when extracting the freeze filter
+        # that specifies which parameters should be frozen during LoRA finetuning.
+        freeze_filter=pi0_fast.Pi0FASTConfig(
+            action_dim=7, action_horizon=10, max_token_len=180, paligemma_variant="gemma_2b_lora"
+        ).get_freeze_filter(),
+        # Turn off EMA for LoRA finetuning.
+        ema_decay=None,
+    ),
+    TrainConfig(
+        name="pi05_libero",
+        model=pi0_config.Pi0Config(pi05=True, action_horizon=10, discrete_state_input=False),
+        data=LeRobotLiberoDataConfig(
+            repo_id="physical-intelligence/libero",
+            base_config=DataConfig(prompt_from_task=True),
+            extra_delta_transform=False,
+        ),
+        batch_size=256,
+        lr_schedule=_optimizer.CosineDecaySchedule(
+            warmup_steps=10_000,
+            peak_lr=5e-5,
+            decay_steps=1_000_000,
+            decay_lr=5e-5,
+        ),
+        optimizer=_optimizer.AdamW(clip_gradient_norm=1.0),
+        ema_decay=0.999,
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi05_base/params"),
+        pytorch_weight_path="/path/to/your/pytorch_weight_path",
+        num_train_steps=30_000,
+    ),
+    TrainConfig(
+        name="pi05_ur_demo_state",
+        model=pi0_config.Pi0Config(
+            pi05=True,
+            action_horizon=10,
+            discrete_state_input=True,
+        ),
+        data=LeRobotURDataConfig(
+            repo_id="ur_demo",
+            base_config=DataConfig(prompt_from_task=True),
+        ),
+        batch_size=256,
+        lr_schedule=_optimizer.CosineDecaySchedule(
+            warmup_steps=10_000,
+            peak_lr=5e-5,
+            decay_steps=1_000_000,
+            decay_lr=5e-5,
+        ),
+        optimizer=_optimizer.AdamW(clip_gradient_norm=1.0),
+        ema_decay=0.999,
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi05_base/params"),
+        num_train_steps=30_000,
+    ),
+    TrainConfig(
+        name="pi05_ur_demo_no_state",
+        model=pi0_config.Pi0Config(
+            pi05=True,
+            action_horizon=10,
+            discrete_state_input=False,
+        ),
+        data=LeRobotURDataConfig(
+            repo_id="ur_demo",
+            base_config=DataConfig(prompt_from_task=True),
+        ),
+        batch_size=256,
+        lr_schedule=_optimizer.CosineDecaySchedule(
+            warmup_steps=10_000,
+            peak_lr=5e-5,
+            decay_steps=1_000_000,
+            decay_lr=5e-5,
+        ),
+        optimizer=_optimizer.AdamW(clip_gradient_norm=1.0),
+        ema_decay=0.999,
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi05_base/params"),
+        num_train_steps=30_000,
+    ),
+    #
+    # Fine-tuning Aloha configs.
+    #
+    # This is a test config that is used to illustate how train on a custom LeRobot dataset.
+    # For instructions on how to convert and train on your own Aloha dataset see examples/aloha_real/README.md
+    TrainConfig(
+        name="pi0_aloha_pen_uncap",
+        model=pi0_config.Pi0Config(),
+        data=LeRobotAlohaDataConfig(
+            repo_id="physical-intelligence/aloha_pen_uncap_diverse",
+            assets=AssetsConfig(
+                assets_dir="gs://openpi-assets/checkpoints/pi0_base/assets",
+                asset_id="trossen",
+            ),
+            default_prompt="uncap the pen",
+            repack_transforms=_transforms.Group(
+                inputs=[
+                    _transforms.RepackTransform(
+                        {
+                            "images": {
+                                "cam_high": "observation.images.cam_high",
+                                "cam_left_wrist": "observation.images.cam_left_wrist",
+                                "cam_right_wrist": "observation.images.cam_right_wrist",
+                            },
+                            "state": "observation.state",
+                            "actions": "action",
+                        }
+                    )
+                ]
+            ),
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi0_base/params"),
+        num_train_steps=20_000,
+    ),
+    TrainConfig(
+        name="pi05_aloha_pen_uncap",
+        model=pi0_config.Pi0Config(pi05=True),
+        data=LeRobotAlohaDataConfig(
+            repo_id="physical-intelligence/aloha_pen_uncap_diverse",
+            assets=AssetsConfig(
+                assets_dir="gs://openpi-assets/checkpoints/pi05_base/assets",
+                asset_id="trossen",
+            ),
+            default_prompt="uncap the pen",
+            repack_transforms=_transforms.Group(
+                inputs=[
+                    _transforms.RepackTransform(
+                        {
+                            "images": {
+                                "cam_high": "observation.images.cam_high",
+                                "cam_left_wrist": "observation.images.cam_left_wrist",
+                                "cam_right_wrist": "observation.images.cam_right_wrist",
+                            },
+                            "state": "observation.state",
+                            "actions": "action",
+                        }
+                    )
+                ]
+            ),
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi05_base/params"),
+        num_train_steps=20_000,
+        batch_size=64,
+    ),
+    #
+    # Fine-tuning DROID configs.
+    #
+    TrainConfig(
+        # This config is for fine-tuning pi0-FAST-base on the *full* DROID dataset.
+        # We use RLDS data loading to make training on this large dataset tractable.
+        # For fine-tuning on your own DROID dataset, see below.
+        name="pi0_fast_full_droid_finetune",
+        model=pi0_fast.Pi0FASTConfig(
+            action_dim=8,
+            action_horizon=16,
+            max_token_len=180,
+        ),
+        data=RLDSDroidDataConfig(
+            repo_id="droid",
+            # Set this to the path to your DROID RLDS dataset (the parent directory of the `droid` directory).
+            rlds_data_dir="<path_to_droid_rlds_dataset>",
+            action_space=droid_rlds_dataset.DroidActionSpace.JOINT_POSITION,
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi0_fast_base/params"),
+        lr_schedule=_optimizer.CosineDecaySchedule(
+            warmup_steps=1_000,
+            peak_lr=5e-5,
+            decay_steps=1_000_000,
+            decay_lr=5e-5,
+        ),
+        num_train_steps=100_000,  # 100k steps should be sufficient, takes ~2 days on 8x H100s
+        batch_size=256,
+        log_interval=100,
+        save_interval=5000,
+        keep_period=20_000,
+        num_workers=0,  # Important: RLDS DataLoader requires num_workers=0, handles multi-processing internally
+    ),
+    TrainConfig(
+        # This config is for fine-tuning pi05 on the *full* DROID dataset.
+        # We use RLDS data loading to make training on this large dataset tractable.
+        # For fine-tuning on your own DROID dataset, see below.
+        name="pi05_full_droid_finetune",
+        model=pi0_config.Pi0Config(
+            pi05=True,
+            action_dim=32,
+            action_horizon=16,
+        ),
+        data=RLDSDroidDataConfig(
+            repo_id="droid",
+            # Set this to the path to your DROID RLDS dataset (the parent directory of the `droid` directory).
+            rlds_data_dir="/mnt/pi-data/kevin",
+            action_space=droid_rlds_dataset.DroidActionSpace.JOINT_POSITION,
+            assets=AssetsConfig(
+                assets_dir="gs://openpi-assets/checkpoints/pi05_base/assets/",
+                asset_id="droid",
+            ),
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi05_base/params"),
+        lr_schedule=_optimizer.CosineDecaySchedule(
+            warmup_steps=1_000,
+            peak_lr=5e-5,
+            decay_steps=1_000_000,
+            decay_lr=5e-5,
+        ),
+        num_train_steps=100_000,
+        batch_size=256,
+        log_interval=100,
+        save_interval=5000,
+        keep_period=10_000,
+        num_workers=0,  # Important: RLDS DataLoader requires num_workers=0, handles multi-processing internally
+    ),
+    TrainConfig(
+        # This config is for fine-tuning pi05-DROID on a custom (smaller) DROID dataset.
+        # Here, we use LeRobot data format (like for all other fine-tuning examples)
+        # To convert your custom DROID dataset (<10s of hours) to LeRobot format, see examples/droid/convert_droid_data_to_lerobot.py
+        name="pi05_droid_finetune",
+        model=pi0_config.Pi0Config(
+            pi05=True,
+            action_dim=32,  # pi05 is trained with 32-dim actions
+            action_horizon=16,
+        ),
+        data=LeRobotDROIDDataConfig(
+            # Replace with your custom DROID LeRobot dataset repo id.
+            repo_id="your_hf_username/my_droid_dataset",
+            base_config=DataConfig(prompt_from_task=True),
+            assets=AssetsConfig(
+                # Important: reuse the original DROID norm stats during fine-tuning!
+                assets_dir="gs://openpi-assets/checkpoints/pi05_droid/assets",
+                asset_id="droid",
+            ),
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi05_droid/params"),
+        num_train_steps=20_000,
+        batch_size=32,
+    ),
+    #
+    # ALOHA Sim configs. This config is used to demonstrate how to train on a simple simulated environment.
+    #
+    TrainConfig(
+        name="pi0_aloha_sim",
+        model=pi0_config.Pi0Config(),
+        data=LeRobotAlohaDataConfig(
+            repo_id="lerobot/aloha_sim_transfer_cube_human",
+            default_prompt="Transfer cube",
+            use_delta_joint_actions=False,
+        ),
+        weight_loader=weight_loaders.CheckpointWeightLoader("gs://openpi-assets/checkpoints/pi0_base/params"),
+        num_train_steps=20_000,
+    ),
+    #
+    # Debugging configs.
+    #
+    TrainConfig(
+        name="debug",
+        data=FakeDataConfig(),
+        batch_size=2,
+        model=pi0_config.Pi0Config(paligemma_variant="dummy", action_expert_variant="dummy"),
+        save_interval=100,
+        overwrite=True,
+        exp_name="debug",
+        num_train_steps=10,
+        wandb_enabled=False,
+    ),
+    TrainConfig(
+        name="debug_restore",
+        data=FakeDataConfig(),
+        batch_size=2,
+        model=pi0_config.Pi0Config(paligemma_variant="dummy", action_expert_variant="dummy"),
+        weight_loader=weight_loaders.CheckpointWeightLoader("./checkpoints/debug/debug/9/params"),
+        overwrite=True,
+        exp_name="debug",
+        num_train_steps=10,
+        wandb_enabled=False,
+    ),
+    TrainConfig(
+        name="debug_pi05",
+        model=pi0_config.Pi0Config(pi05=True, paligemma_variant="dummy", action_expert_variant="dummy"),
+        data=FakeDataConfig(),
+        batch_size=2,
+        num_train_steps=10,
+        overwrite=True,
+        exp_name="debug_pi05",
+        wandb_enabled=False,
+    ),
+    # RoboArena & PolaRiS configs.
+    *roboarena_config.get_roboarena_configs(),
+    *polaris_config.get_polaris_configs(),
+]
+
+if len({config.name for config in _CONFIGS}) != len(_CONFIGS):
+    raise ValueError("Config names must be unique.")
+_CONFIGS_DICT = {config.name: config for config in _CONFIGS}
+
+
+def cli() -> TrainConfig:
+    return tyro.extras.overridable_config_cli({k: (k, v) for k, v in _CONFIGS_DICT.items()})
+
+
+def get_config(config_name: str) -> TrainConfig:
+    """Get a config by name."""
+    if config_name not in _CONFIGS_DICT:
+        closest = difflib.get_close_matches(config_name, _CONFIGS_DICT.keys(), n=1, cutoff=0.0)
+        closest_str = f" Did you mean '{closest[0]}'? " if closest else ""
+        raise ValueError(f"Config '{config_name}' not found.{closest_str}")
+
+    return _CONFIGS_DICT[config_name]
diff --git a/openpi_runtime/openpi/training/data_loader.py b/openpi_runtime/openpi/training/data_loader.py
new file mode 100644
index 0000000000000000000000000000000000000000..e2ee7dd06b6008757f834405c9222d493f450eb7
--- /dev/null
+++ b/openpi_runtime/openpi/training/data_loader.py
@@ -0,0 +1,540 @@
+from collections.abc import Iterator, Sequence
+import logging
+import multiprocessing
+import os
+import typing
+from typing import Literal, Protocol, SupportsIndex, TypeVar
+
+import jax
+import jax.numpy as jnp
+import lerobot.common.datasets.lerobot_dataset as lerobot_dataset
+import numpy as np
+import torch
+
+import openpi.models.model as _model
+import openpi.training.config as _config
+from openpi.training.droid_rlds_dataset import DroidRldsDataset
+import openpi.transforms as _transforms
+
+T_co = TypeVar("T_co", covariant=True)
+
+
+class Dataset(Protocol[T_co]):
+    """Interface for a dataset with random access."""
+
+    def __getitem__(self, index: SupportsIndex) -> T_co:
+        raise NotImplementedError("Subclasses of Dataset should implement __getitem__.")
+
+    def __len__(self) -> int:
+        raise NotImplementedError("Subclasses of Dataset should implement __len__.")
+
+
+class IterableDataset(Protocol[T_co]):
+    """Interface for an iterable dataset."""
+
+    def __iter__(self) -> Iterator[T_co]:
+        raise NotImplementedError("Subclasses of IterableDataset should implement __iter__.")
+
+    def __len__(self) -> int:
+        raise NotImplementedError("Subclasses of Dataset should implement __len__.")
+
+
+class DataLoader(Protocol[T_co]):
+    """Interface for a data loader."""
+
+    def data_config(self) -> _config.DataConfig:
+        """Get the data config for this data loader."""
+        raise NotImplementedError("Subclasses of DataLoader should implement data_config.")
+
+    def __iter__(self) -> Iterator[T_co]:
+        raise NotImplementedError("Subclasses of DataLoader should implement __iter__.")
+
+
+class TransformedDataset(Dataset[T_co]):
+    def __init__(self, dataset: Dataset, transforms: Sequence[_transforms.DataTransformFn]):
+        self._dataset = dataset
+        self._transform = _transforms.compose(transforms)
+
+    def __getitem__(self, index: SupportsIndex) -> T_co:
+        return self._transform(self._dataset[index])
+
+    def __len__(self) -> int:
+        return len(self._dataset)
+
+
+class IterableTransformedDataset(IterableDataset[T_co]):
+    def __init__(
+        self,
+        dataset: IterableDataset,
+        transforms: Sequence[_transforms.DataTransformFn],
+        *,
+        is_batched: bool = False,
+    ):
+        self._dataset = dataset
+        self._transform = _transforms.compose(transforms)
+        self._is_batched = is_batched
+
+    def __iter__(self):
+        for sample in self._dataset:
+            if self._is_batched:
+                # Transforms are designed to be applied to individual samples. So we need to split the batch into
+                # individual samples and apply the transform to each sample individually.
+                batch_size = next(v.shape[0] for v in sample.values())
+
+                # Split batch into individual samples using tree_map
+                individual_samples = [jax.tree.map(lambda x: x[i], sample) for i in range(batch_size)]  # noqa: B023
+
+                # Transform each sample
+                transformed = [self._transform(s) for s in individual_samples]
+
+                # Recombine batch with tree_map
+                yield jax.tree.map(lambda *x: np.stack(x, axis=0), *transformed)
+            else:
+                yield self._transform(sample)
+
+    def __len__(self) -> int:
+        return len(self._dataset)
+
+
+class FakeDataset(Dataset):
+    def __init__(self, model_config: _model.BaseModelConfig, num_samples: int):
+        self._num_samples = num_samples
+        self._observation_spec, self._action_spec = model_config.inputs_spec()
+
+    def __getitem__(self, index: SupportsIndex) -> dict:
+        rng = jax.random.key(index.__index__())
+
+        def make_from_spec(spec: jax.ShapeDtypeStruct):
+            nonlocal rng
+            rng, data_rng = jax.random.split(rng)
+            # Remove the batch dimension.
+            shape = spec.shape[1:]
+            if spec.dtype == jnp.float32:
+                return jax.random.uniform(data_rng, shape=shape, minval=-1.0, maxval=1.0)
+            if spec.dtype == jnp.int32:
+                return jax.random.randint(data_rng, shape=shape, minval=0, maxval=2048)
+            return jnp.zeros(shape=shape, dtype=spec.dtype)
+
+        observation = jax.tree.map(make_from_spec, self._observation_spec)
+        action = jax.tree.map(make_from_spec, self._action_spec)
+
+        return {
+            **observation.to_dict(),
+            "actions": action,
+        }
+
+    def __len__(self) -> int:
+        return self._num_samples
+
+
+def create_torch_dataset(
+    data_config: _config.DataConfig, action_horizon: int, model_config: _model.BaseModelConfig
+) -> Dataset:
+    """Create a dataset for training."""
+    repo_id = data_config.repo_id
+    if repo_id is None:
+        raise ValueError("Repo ID is not set. Cannot create dataset.")
+    if repo_id == "fake":
+        return FakeDataset(model_config, num_samples=1024)
+
+    dataset_meta = lerobot_dataset.LeRobotDatasetMetadata(repo_id)
+    dataset = lerobot_dataset.LeRobotDataset(
+        data_config.repo_id,
+        delta_timestamps={
+            key: [t / dataset_meta.fps for t in range(action_horizon)] for key in data_config.action_sequence_keys
+        },
+    )
+
+    if data_config.prompt_from_task:
+        dataset = TransformedDataset(dataset, [_transforms.PromptFromLeRobotTask(dataset_meta.tasks)])
+
+    return dataset
+
+
+def create_rlds_dataset(
+    data_config: _config.DataConfig,
+    action_horizon: int,
+    batch_size: int,
+    *,
+    shuffle: bool = False,
+) -> Dataset:
+    # At the moment, we only support DROID for RLDS datasets.
+    return DroidRldsDataset(
+        data_dir=data_config.rlds_data_dir,
+        batch_size=batch_size,
+        shuffle=shuffle,
+        action_chunk_size=action_horizon,
+        action_space=data_config.action_space,
+        datasets=data_config.datasets,
+    )
+
+
+def transform_dataset(dataset: Dataset, data_config: _config.DataConfig, *, skip_norm_stats: bool = False) -> Dataset:
+    """Transform the dataset by applying the data transforms."""
+    norm_stats = {}
+    if data_config.repo_id != "fake" and not skip_norm_stats:
+        if data_config.norm_stats is None:
+            raise ValueError(
+                "Normalization stats not found. "
+                "Make sure to run `scripts/compute_norm_stats.py --config-name=<your-config>`."
+            )
+        norm_stats = data_config.norm_stats
+
+    return TransformedDataset(
+        dataset,
+        [
+            *data_config.repack_transforms.inputs,
+            *data_config.data_transforms.inputs,
+            _transforms.Normalize(norm_stats, use_quantiles=data_config.use_quantile_norm),
+            *data_config.model_transforms.inputs,
+        ],
+    )
+
+
+def transform_iterable_dataset(
+    dataset: IterableDataset,
+    data_config: _config.DataConfig,
+    *,
+    skip_norm_stats: bool = False,
+    is_batched: bool = False,
+) -> IterableDataset:
+    """Transform the dataset by applying the data transforms."""
+    norm_stats = {}
+    if data_config.repo_id != "fake" and not skip_norm_stats:
+        if data_config.norm_stats is None:
+            raise ValueError(
+                "Normalization stats not found. "
+                "Make sure to run `scripts/compute_norm_stats.py --config-name=<your-config>`."
+            )
+        norm_stats = data_config.norm_stats
+
+    return IterableTransformedDataset(
+        dataset,
+        [
+            *data_config.repack_transforms.inputs,
+            *data_config.data_transforms.inputs,
+            _transforms.Normalize(norm_stats, use_quantiles=data_config.use_quantile_norm),
+            *data_config.model_transforms.inputs,
+        ],
+        is_batched=is_batched,
+    )
+
+
+def create_data_loader(
+    config: _config.TrainConfig,
+    *,
+    sharding: jax.sharding.Sharding | None = None,
+    shuffle: bool = False,
+    num_batches: int | None = None,
+    skip_norm_stats: bool = False,
+    framework: Literal["jax", "pytorch"] = "jax",
+) -> DataLoader[tuple[_model.Observation, _model.Actions]]:
+    """Create a data loader for training.
+
+    Args:
+        config: The training configuration.
+        sharding: The sharding to use for the data loader (JAX only).
+        shuffle: Whether to shuffle the data.
+        num_batches: Determines the number of batches to return.
+        skip_norm_stats: Whether to skip data normalization.
+        framework: The framework to use ("jax" or "pytorch").
+    """
+    data_config = config.data.create(config.assets_dirs, config.model)
+    logging.info(f"data_config: {data_config}")
+
+    if data_config.rlds_data_dir is not None:
+        return create_rlds_data_loader(
+            data_config,
+            action_horizon=config.model.action_horizon,
+            batch_size=config.batch_size,
+            sharding=sharding,
+            shuffle=shuffle,
+            num_batches=num_batches,
+            skip_norm_stats=skip_norm_stats,
+            framework=framework,
+        )
+    return create_torch_data_loader(
+        data_config,
+        model_config=config.model,
+        action_horizon=config.model.action_horizon,
+        batch_size=config.batch_size,
+        sharding=sharding,
+        shuffle=shuffle,
+        num_batches=num_batches,
+        num_workers=config.num_workers,
+        seed=config.seed,
+        skip_norm_stats=skip_norm_stats,
+        framework=framework,
+    )
+
+
+def create_torch_data_loader(
+    data_config: _config.DataConfig,
+    model_config: _model.BaseModelConfig,
+    action_horizon: int,
+    batch_size: int,
+    *,
+    sharding: jax.sharding.Sharding | None = None,
+    skip_norm_stats: bool = False,
+    shuffle: bool = False,
+    num_batches: int | None = None,
+    num_workers: int = 0,
+    seed: int = 0,
+    framework: str = "jax",
+) -> DataLoader[tuple[_model.Observation, _model.Actions]]:
+    """Create a data loader for training.
+
+    Args:
+        data_config: The data configuration.
+        action_horizon: The action horizon.
+        batch_size: The batch size.
+        sharding: The sharding to use for the data loader. If None, the data loader will
+            use a single device sharding.
+        skip_norm_stats: Whether to skip data normalization.
+        shuffle: Whether to shuffle the data.
+        num_batches: Determines the number of batches to return. If the number exceeds the
+            number of batches in the dataset, the data loader will loop over the dataset.
+            If not provided, will iterate over the dataset indefinitely.
+        num_workers: The number of worker processes to use. If zero, the data loader will
+            execute in the main process.
+        seed: The seed to use for shuffling the data.
+    """
+    dataset = create_torch_dataset(data_config, action_horizon, model_config)
+    dataset = transform_dataset(dataset, data_config, skip_norm_stats=skip_norm_stats)
+
+    # Use TorchDataLoader for both frameworks
+    # For PyTorch DDP, create DistributedSampler and divide batch size by world size
+    # For JAX, divide by process count
+    sampler = None
+    if framework == "pytorch":
+        if torch.distributed.is_initialized():
+            sampler = torch.utils.data.distributed.DistributedSampler(
+                dataset,
+                num_replicas=torch.distributed.get_world_size(),
+                rank=torch.distributed.get_rank(),
+                shuffle=shuffle,
+                drop_last=True,
+            )
+            local_batch_size = batch_size // torch.distributed.get_world_size()
+        else:
+            local_batch_size = batch_size
+    else:
+        local_batch_size = batch_size // jax.process_count()
+
+    logging.info(f"local_batch_size: {local_batch_size}")
+    data_loader = TorchDataLoader(
+        dataset,
+        local_batch_size=local_batch_size,
+        sharding=None if framework == "pytorch" else sharding,
+        shuffle=(sampler is None and shuffle),  # Don't shuffle if using sampler
+        sampler=sampler,
+        num_batches=num_batches,
+        num_workers=num_workers,
+        seed=seed,
+        framework=framework,
+    )
+
+    return DataLoaderImpl(data_config, data_loader)
+
+
+def create_rlds_data_loader(
+    data_config: _config.DataConfig,
+    action_horizon: int,
+    batch_size: int,
+    *,
+    sharding: jax.sharding.Sharding | None = None,
+    skip_norm_stats: bool = False,
+    shuffle: bool = False,
+    num_batches: int | None = None,
+    framework: str = "jax",
+) -> DataLoader[tuple[_model.Observation, _model.Actions]]:
+    """Create an RLDS data loader for training.
+
+    Note: This data loader requires some extra dependencies -- see examples/droid/README_train.md
+
+    Args:
+        data_config: The data configuration.
+        action_horizon: The action horizon.
+        batch_size: The batch size.
+        sharding: The sharding to use for the data loader. If None, the data loader will
+            use a single device sharding.
+        skip_norm_stats: Whether to skip data normalization.
+        shuffle: Whether to shuffle the data.
+        num_batches: Determines the number of batches to return. If the number exceeds the
+            number of batches in the dataset, the data loader will loop over the dataset.
+            If not provided, will iterate over the dataset indefinitely.
+    """
+    if framework == "pytorch":
+        raise NotImplementedError("PyTorch RLDS data loader is not supported yet")
+    dataset = create_rlds_dataset(data_config, action_horizon, batch_size, shuffle=shuffle)
+    dataset = transform_iterable_dataset(dataset, data_config, skip_norm_stats=skip_norm_stats, is_batched=True)
+
+    data_loader = RLDSDataLoader(
+        dataset,
+        sharding=sharding,
+        num_batches=num_batches,
+    )
+
+    return DataLoaderImpl(data_config, data_loader)
+
+
+class TorchDataLoader:
+    """Torch data loader implementation."""
+
+    def __init__(
+        self,
+        dataset,
+        local_batch_size: int,
+        *,
+        sharding: jax.sharding.Sharding | None = None,
+        shuffle: bool = False,
+        sampler: torch.utils.data.Sampler | None = None,
+        num_batches: int | None = None,
+        num_workers: int = 0,
+        seed: int = 0,
+        framework: str = "jax",
+    ):
+        """Create a PyTorch data loader.
+
+        Args:
+            dataset: The dataset to load.
+            local_batch_size: The local batch size for each process.
+            sharding: The sharding to use for the data loader.
+            shuffle: Whether to shuffle the data.
+            num_batches: If provided, determines the number of returned batches. If the
+                number is larger than the number of batches in the dataset, the data loader
+                will loop over the dataset. If not provided, will iterate over the dataset
+                indefinitely.
+            num_workers: The number of worker processes to use. If zero, the data loader will
+                execute in the main process.
+            seed: The seed to use for shuffling the data.
+        """
+        if jax.process_count() > 1:
+            raise NotImplementedError("Data loading with multiple processes is not supported.")
+
+        if len(dataset) < local_batch_size:
+            raise ValueError(f"Local batch size ({local_batch_size}) is larger than the dataset size ({len(dataset)}).")
+
+        # Store sharding - None for PyTorch, JAX sharding for JAX
+        self._sharding = sharding
+        if sharding is None and framework == "jax":
+            # Use data parallel sharding by default for JAX only.
+            self._sharding = jax.sharding.NamedSharding(
+                jax.sharding.Mesh(jax.devices(), ("B",)),
+                jax.sharding.PartitionSpec("B"),
+            )
+        self._num_batches = num_batches
+
+        mp_context = None
+        if num_workers > 0:
+            mp_context = multiprocessing.get_context("spawn")
+
+        generator = torch.Generator()
+        generator.manual_seed(seed)
+        self._data_loader = torch.utils.data.DataLoader(
+            typing.cast(torch.utils.data.Dataset, dataset),
+            batch_size=local_batch_size,
+            shuffle=(sampler is None and shuffle),  # Don't shuffle if using sampler
+            sampler=sampler,
+            num_workers=num_workers,
+            multiprocessing_context=mp_context,
+            persistent_workers=num_workers > 0,
+            collate_fn=_collate_fn,
+            worker_init_fn=_worker_init_fn,
+            drop_last=True,
+            generator=generator,
+        )
+
+    @property
+    def torch_loader(self) -> torch.utils.data.DataLoader:
+        return self._data_loader
+
+    def __iter__(self):
+        num_items = 0
+        while True:
+            data_iter = iter(self._data_loader)
+            while True:
+                if self._num_batches is not None and num_items >= self._num_batches:
+                    return
+                try:
+                    batch = next(data_iter)
+                except StopIteration:
+                    break  # We've exhausted the dataset. Create a new iterator and start over.
+                num_items += 1
+                # For JAX, convert to sharded arrays; for PyTorch, return torch tensors
+                if self._sharding is not None:
+                    yield jax.tree.map(lambda x: jax.make_array_from_process_local_data(self._sharding, x), batch)
+                else:
+                    yield jax.tree.map(torch.as_tensor, batch)
+
+
+def _collate_fn(items):
+    """Collate the batch elements into batched numpy arrays."""
+    # Make sure to convert to numpy arrays before stacking since some of the incoming elements
+    # may be JAX arrays.
+    return jax.tree.map(lambda *xs: np.stack([np.asarray(x) for x in xs], axis=0), *items)
+
+
+def _worker_init_fn(worker_id: int) -> None:
+    """Tell JAX inside the worker process not to preallocate the GPU memory."""
+    # NOTE: This is called after jax is imported inside the worker process. This
+    # means that this approach will not work for selecting the backend.
+    os.environ["XLA_PYTHON_CLIENT_PREALLOCATE"] = "false"
+    os.environ["XLA_PYTHON_CLIENT_ALLOCATOR"] = "platform"
+
+
+class RLDSDataLoader:
+    """Shallow wrapper around the DROID data loader to make it compatible with openpi.
+
+    All batching already happens in the DROID dataset, so we don't need to do anything here.
+    """
+
+    def __init__(
+        self,
+        dataset: DroidRldsDataset,
+        *,
+        sharding: jax.sharding.Sharding | None = None,
+        num_batches: int | None = None,
+    ):
+        self._dataset = dataset
+        self._num_batches = num_batches
+
+        if jax.process_count() > 1:
+            raise NotImplementedError("Data loading with multiple processes is not supported.")
+
+        if sharding is None:
+            # Use data parallel sharding by default.
+            sharding = jax.sharding.NamedSharding(
+                jax.sharding.Mesh(jax.devices(), ("B",)),
+                jax.sharding.PartitionSpec("B"),
+            )
+
+        self._sharding = sharding
+        self._num_batches = num_batches
+
+    def __iter__(self):
+        num_items = 0
+        while True:
+            data_iter = iter(self._dataset)
+            while True:
+                if self._num_batches is not None and num_items >= self._num_batches:
+                    return
+                try:
+                    batch = next(data_iter)
+                except StopIteration:
+                    break  # We've exhausted the dataset. Create a new iterator and start over.
+                num_items += 1
+                yield jax.tree.map(lambda x: jax.make_array_from_process_local_data(self._sharding, x), batch)
+
+
+class DataLoaderImpl(DataLoader):
+    def __init__(self, data_config: _config.DataConfig, data_loader: TorchDataLoader | RLDSDataLoader):
+        self._data_config = data_config
+        self._data_loader = data_loader
+
+    def data_config(self) -> _config.DataConfig:
+        return self._data_config
+
+    def __iter__(self):
+        for batch in self._data_loader:
+            yield _model.Observation.from_dict(batch), batch["actions"]
diff --git a/openpi_runtime/openpi/training/droid_rlds_dataset.py b/openpi_runtime/openpi/training/droid_rlds_dataset.py
new file mode 100644
index 0000000000000000000000000000000000000000..2cb08a16ac1817dd271fb2e2750fc3aa1a079bd4
--- /dev/null
+++ b/openpi_runtime/openpi/training/droid_rlds_dataset.py
@@ -0,0 +1,248 @@
+"""
+RLDS-based data loader for DROID.
+While openpi typically uses LeRobot's data loader, it is not currently scalable enough for larger datasets like DROID.
+Thus, we provide a data loader example here that uses the RLDS data format.
+The data loader also applies a few DROID-specific data filters / transformations.
+"""
+
+from collections.abc import Sequence
+import dataclasses
+from enum import Enum
+from enum import auto
+import json
+import logging
+from pathlib import Path
+
+import tqdm
+
+import openpi.shared.download as download
+
+
+class DroidActionSpace(Enum):
+    """Action space for DROID dataset."""
+
+    JOINT_POSITION = auto()
+    JOINT_VELOCITY = auto()
+
+
+@dataclasses.dataclass
+class RLDSDataset:
+    name: str
+    version: str
+    weight: float
+    filter_dict_path: str | None = None
+
+
+class DroidRldsDataset:
+    def __init__(
+        self,
+        data_dir: str,
+        batch_size: int,
+        datasets: Sequence[RLDSDataset],
+        *,  # Force keyword-only arguments
+        shuffle: bool = True,
+        action_chunk_size: int = 16,
+        # We default to joint position actions, since they allow policy evaluation in simulation.
+        action_space: DroidActionSpace = DroidActionSpace.JOINT_POSITION,
+        max_loaded_steps_per_episode: int = 100,
+        # Reduce this if you are running out of memory, but careful -- below ~100k shuffling is not sufficiently random.
+        shuffle_buffer_size: int = 250_000,
+        num_parallel_reads: int = -1,  # -1 == tf.data.AUTOTUNE -- hack to not import tf at top level
+        num_parallel_calls: int = -1,  # -1 == tf.data.AUTOTUNE -- hack to not import tf at top level
+    ):
+        # Import tensorflow here to not make it mandatory in case RLDS data loader is not used.
+        import dlimp as dl
+        import tensorflow as tf
+        import tensorflow_datasets as tfds
+
+        # Configure Tensorflow with *no GPU devices* (to prevent clobber with PyTorch / JAX)
+        tf.config.set_visible_devices([], "GPU")
+
+        # Ensure dataset weights sum to 1.0
+        assert sum(dataset.weight for dataset in datasets) == 1.0, "Dataset weights must sum to 1.0"
+
+        def prepare_single_dataset(dataset_cfg: RLDSDataset):
+            # ds_name, version = dataset_name.split(":")
+            ds_name, version = dataset_cfg.name, dataset_cfg.version
+            builder = tfds.builder(ds_name, data_dir=data_dir, version=version)
+            dataset = dl.DLataset.from_rlds(
+                builder, split="train", shuffle=shuffle, num_parallel_reads=num_parallel_reads
+            )
+
+            # Filter out any unsuccessful trajectories -- we use the file name to check this
+            dataset = dataset.filter(
+                lambda traj: tf.strings.regex_full_match(
+                    traj["traj_metadata"]["episode_metadata"]["file_path"][0], ".*success.*"
+                )
+            )
+
+            # Repeat dataset so we never run out of data.
+            dataset = dataset.repeat()
+
+            # Load the filter dictionary if provided.
+            # The filter dictionary is a JSON file that maps episode keys to ranges of frames to sample
+            # (e.g.,
+            # {
+            #     "<episode key>": [[0, 100], [200, 300]]
+            # }
+            # means keep frames 0-99 and 200-299).
+
+            filter_dict_path = dataset_cfg.filter_dict_path
+            if filter_dict_path is not None:
+                cached_filter_dict_path = download.maybe_download(filter_dict_path)
+                with Path(cached_filter_dict_path).open("r") as f:
+                    filter_dict = json.load(f)
+                logging.info(f"Using filter dictionary with {len(filter_dict)} episodes")
+
+                keys_tensor = []
+                values_tensor = []
+
+                for episode_key, ranges in tqdm.tqdm(filter_dict.items(), desc="Creating idle filter hash table..."):
+                    for start, end in ranges:
+                        for t in range(start, end):
+                            frame_key = f"{episode_key}--{t}"
+                            keys_tensor.append(frame_key)
+                            values_tensor.append(True)
+                self.filter_table = tf.lookup.StaticHashTable(
+                    tf.lookup.KeyValueTensorInitializer(keys_tensor, values_tensor), default_value=False
+                )
+                logging.info("Filter hash table initialized")
+            else:
+                self.filter_table = tf.lookup.StaticHashTable(
+                    tf.lookup.KeyValueTensorInitializer([""], [True]), default_value=True
+                )
+
+            def restructure(traj):
+                """Reformat observation and action keys, sample language instruction."""
+                # Important: we use joint *position* action space -- easier to simulate!
+                actions = tf.concat(
+                    (
+                        (
+                            traj["action_dict"]["joint_position"]
+                            if action_space == DroidActionSpace.JOINT_POSITION
+                            else traj["action_dict"]["joint_velocity"]
+                        ),
+                        traj["action_dict"]["gripper_position"],
+                    ),
+                    axis=-1,
+                )
+                # Randomly samples one of the two exterior images in DROID during training (we only train with one at a time).
+                # Note: the "left" refers to the left camera in the stereo pair, we only train on the left camera.
+                exterior_img = tf.cond(
+                    tf.random.uniform(shape=[]) > 0.5,
+                    lambda: traj["observation"]["exterior_image_1_left"],
+                    lambda: traj["observation"]["exterior_image_2_left"],
+                )
+                wrist_img = traj["observation"]["wrist_image_left"]
+                # Randomly sample one of the three language instructions
+                instruction = tf.random.shuffle(
+                    [traj["language_instruction"], traj["language_instruction_2"], traj["language_instruction_3"]]
+                )[0]
+
+                traj_len = tf.shape(traj["action"])[0]
+                indices = tf.as_string(tf.range(traj_len))
+
+                # Data filtering:
+                # Compute a uniquely-identifying step ID by concatenating the recording folderpath, file path,
+                # and each step's time step index. This will index into the filter hash table, and if it returns true,
+                # then the frame passes the filter.
+                step_id = (
+                    traj["traj_metadata"]["episode_metadata"]["recording_folderpath"]
+                    + "--"
+                    + traj["traj_metadata"]["episode_metadata"]["file_path"]
+                    + "--"
+                    + indices
+                )
+                passes_filter = self.filter_table.lookup(step_id)
+
+                return {
+                    "actions": actions,
+                    "observation": {
+                        "image": exterior_img,
+                        "wrist_image": wrist_img,
+                        "joint_position": traj["observation"]["joint_position"],
+                        "gripper_position": traj["observation"]["gripper_position"],
+                    },
+                    "prompt": instruction,
+                    "step_id": step_id,
+                    "passes_filter": passes_filter,
+                }
+
+            dataset = dataset.traj_map(restructure, num_parallel_calls)
+
+            def chunk_actions(traj):
+                """Splits episode into action chunks."""
+                traj_len = tf.shape(traj["actions"])[0]
+
+                # For each step in the trajectory, construct indices for the next n actions
+                action_chunk_indices = tf.broadcast_to(
+                    tf.range(action_chunk_size)[None],
+                    [traj_len, action_chunk_size],
+                ) + tf.broadcast_to(
+                    tf.range(traj_len)[:, None],
+                    [traj_len, action_chunk_size],
+                )
+
+                # Cap to length of the sequence --> final chunks will repeat the last action
+                # This makes sense, since we are using absolute joint + gripper position actions
+                action_chunk_indices = tf.minimum(action_chunk_indices, traj_len - 1)
+
+                # Gather the actions for each chunk
+                traj["actions"] = tf.gather(traj["actions"], action_chunk_indices)
+                return traj
+
+            dataset = dataset.traj_map(chunk_actions, num_parallel_calls)
+
+            # Flatten: map from trajectory dataset to dataset of individual action chunks
+            dataset = dataset.flatten(num_parallel_calls=num_parallel_calls)
+
+            # Filter data that doesn't pass the filter
+            def filter_from_dict(frame):
+                return frame["passes_filter"]
+
+            dataset = dataset.filter(filter_from_dict)
+
+            # Remove "passes_filter" key from output
+            def remove_passes_filter(frame):
+                frame.pop("passes_filter")
+                return frame
+
+            dataset = dataset.map(remove_passes_filter)
+
+            # Decode images: RLDS saves encoded images, only decode now for efficiency
+            def decode_images(traj):
+                traj["observation"]["image"] = tf.io.decode_image(
+                    traj["observation"]["image"], expand_animations=False, dtype=tf.uint8
+                )
+                traj["observation"]["wrist_image"] = tf.io.decode_image(
+                    traj["observation"]["wrist_image"], expand_animations=False, dtype=tf.uint8
+                )
+                return traj
+
+            return dataset.frame_map(decode_images, num_parallel_calls)
+
+        logging.info(f"Preparing {len(datasets)} datasets...")
+        logging.info("-" * 50)
+        for dataset in datasets:
+            logging.info(f"    {dataset.name}:{dataset.version} with weight {dataset.weight:.2f}")
+        logging.info("-" * 50)
+        all_datasets = [prepare_single_dataset(dataset) for dataset in datasets]
+        weights = [dataset.weight for dataset in datasets]
+
+        final_dataset = dl.DLataset.sample_from_datasets(all_datasets, weights=weights)
+        final_dataset = final_dataset.shuffle(shuffle_buffer_size)
+        final_dataset = final_dataset.batch(batch_size)
+        # Note =>> Seems to reduce memory usage without affecting speed?
+        final_dataset = final_dataset.with_ram_budget(1)
+
+        self.dataset = final_dataset
+        self.batch_size = batch_size
+        self.shuffle = shuffle
+
+    def __iter__(self):
+        yield from self.dataset.as_numpy_iterator()
+
+    def __len__(self):
+        # This is the approximate number of samples in DROID after filtering.
+        # Easier to hardcode than to iterate through the dataset and compute it.
+        return 20_000_000
diff --git a/openpi_runtime/openpi/training/misc/polaris_config.py b/openpi_runtime/openpi/training/misc/polaris_config.py
new file mode 100644
index 0000000000000000000000000000000000000000..873beb22fec30e216997ba2455d44a3cb1b304dd
--- /dev/null
+++ b/openpi_runtime/openpi/training/misc/polaris_config.py
@@ -0,0 +1,225 @@
+"""PolaRiS baseline policy configs."""
+
+from typing import TypeAlias
+
+import openpi.models.model as _model
+import openpi.models.pi0_config as pi0_config
+import openpi.models.pi0_fast as pi0_fast
+import openpi.models.tokenizer as _tokenizer
+import openpi.policies.droid_policy as droid_policy
+import openpi.training.droid_rlds_dataset as droid_rlds_dataset
+import openpi.training.optimizer as _optimizer
+import openpi.training.weight_loaders as weight_loaders
+import openpi.transforms as _transforms
+
+ModelType: TypeAlias = _model.ModelType
+
+
+def get_polaris_configs():
+    # Import here to avoid circular imports.
+    from openpi.training.config import AssetsConfig
+    from openpi.training.config import RLDSDroidDataConfig
+    from openpi.training.config import SimpleDataConfig
+    from openpi.training.config import TrainConfig
+
+    return [
+        #
+        # PolaRiS DROID jointpos policies
+        #
+        TrainConfig(
+            name="pi05_droid_jointpos_polaris",
+            model=pi0_config.Pi0Config(action_horizon=15, pi05=True),
+            data=RLDSDroidDataConfig(
+                assets=AssetsConfig(
+                    assets_dir="gs://openpi-assets/checkpoints/polaris/pi05_droid_jointpos_polaris/assets",
+                    asset_id="droid",
+                ),
+                datasets=(
+                    droid_rlds_dataset.RLDSDataset(
+                        name="droid",
+                        version="1.0.1",
+                        weight=0.9,
+                        filter_dict_path="gs://openpi-assets/droid/droid_sample_ranges_v1_0_1.json",
+                    ),
+                    droid_rlds_dataset.RLDSDataset(
+                        name="polaris_droid_cotrain_dataset",
+                        version="1.0.0",
+                        weight=0.1,
+                        filter_dict_path="gs://openpi-assets/droid/polaris_droid_cotrain_dataset_sample_ranges_v1_0_0.json",
+                    ),
+                ),
+                rlds_data_dir="<path_to_droid_rlds_dataset>",
+                action_space=droid_rlds_dataset.DroidActionSpace.JOINT_POSITION,
+            ),
+            weight_loader=weight_loaders.CheckpointWeightLoader(
+                "gs://openpi-assets/checkpoints/polaris/pi05_droid_jointpos_polaris/params"
+            ),
+            lr_schedule=_optimizer.CosineDecaySchedule(
+                warmup_steps=1_000,
+                peak_lr=5e-5,
+                decay_steps=1_000_000,
+                decay_lr=5e-5,
+            ),
+            num_train_steps=1_000,
+            batch_size=128,
+            log_interval=100,
+            save_interval=1000,
+            keep_period=1000,
+            num_workers=0,  # Important: RLDS DataLoader requires num_workers=0, handles multi-processing internally
+        ),
+        TrainConfig(
+            name="pi0_fast_droid_jointpos_polaris",
+            model=pi0_fast.Pi0FASTConfig(
+                action_dim=8,
+                action_horizon=10,
+                max_token_len=180,
+            ),
+            data=RLDSDroidDataConfig(
+                assets=AssetsConfig(
+                    assets_dir="gs://openpi-assets/checkpoints/polaris/pi0_fast_droid_jointpos_polaris/assets",
+                    asset_id="droid",
+                ),
+                datasets=(
+                    droid_rlds_dataset.RLDSDataset(
+                        name="droid",
+                        version="1.0.1",
+                        weight=0.9,
+                        filter_dict_path="gs://openpi-assets/droid/droid_sample_ranges_v1_0_1.json",
+                    ),
+                    droid_rlds_dataset.RLDSDataset(
+                        name="polaris_droid_cotrain_dataset",
+                        version="1.0.0",
+                        weight=0.1,
+                        filter_dict_path="gs://openpi-assets/droid/polaris_droid_cotrain_dataset_sample_ranges_v1_0_0.json",
+                    ),
+                ),
+                rlds_data_dir="<path_to_droid_rlds_dataset>",
+                action_space=droid_rlds_dataset.DroidActionSpace.JOINT_POSITION,
+            ),
+            weight_loader=weight_loaders.CheckpointWeightLoader(
+                "gs://openpi-assets/checkpoints/polaris/pi0_fast_droid_jointpos_polaris/params"
+            ),
+            lr_schedule=_optimizer.CosineDecaySchedule(
+                warmup_steps=1_000,
+                peak_lr=5e-5,
+                decay_steps=1_000_000,
+                decay_lr=5e-5,
+            ),
+            num_train_steps=1_000,
+            batch_size=128,
+            log_interval=100,
+            save_interval=1000,
+            keep_period=1000,
+            num_workers=0,  # Important: RLDS DataLoader requires num_workers=0, handles multi-processing internally
+        ),
+        TrainConfig(
+            name="pi0_droid_jointpos_polaris",
+            model=pi0_config.Pi0Config(
+                # action_dim=8, # leave as 32 default...
+                action_horizon=10,
+                max_token_len=100,
+            ),
+            data=RLDSDroidDataConfig(
+                assets=AssetsConfig(
+                    assets_dir="gs://openpi-assets/checkpoints/polaris/pi0_droid_jointpos_polaris/assets",
+                    asset_id="droid",
+                ),
+                datasets=(
+                    droid_rlds_dataset.RLDSDataset(
+                        name="droid",
+                        version="1.0.1",
+                        weight=0.9,
+                        filter_dict_path="gs://openpi-assets/droid/droid_sample_ranges_v1_0_1.json",
+                    ),
+                    droid_rlds_dataset.RLDSDataset(
+                        name="polaris_droid_cotrain_dataset",
+                        version="1.0.0",
+                        weight=0.1,
+                        filter_dict_path="gs://openpi-assets/droid/polaris_droid_cotrain_dataset_sample_ranges_v1_0_0.json",
+                    ),
+                ),
+                rlds_data_dir="<path_to_droid_rlds_dataset>",
+                action_space=droid_rlds_dataset.DroidActionSpace.JOINT_POSITION,
+            ),
+            weight_loader=weight_loaders.CheckpointWeightLoader(
+                "gs://openpi-assets/checkpoints/polaris/pi0_droid_jointpos_polaris/params"
+            ),
+            lr_schedule=_optimizer.CosineDecaySchedule(
+                warmup_steps=1_000,
+                peak_lr=5e-5,
+                decay_steps=1_000_000,
+                decay_lr=5e-5,
+            ),
+            num_train_steps=1_000,
+            batch_size=128,
+            log_interval=100,
+            save_interval=1000,
+            keep_period=1000,
+            num_workers=0,  # Important: RLDS DataLoader requires num_workers=0, handles multi-processing internally
+        ),
+        TrainConfig(
+            name="pi0_droid_jointpos_100k_polaris",
+            model=pi0_config.Pi0Config(
+                # action_dim=8, # leave as 32 default...
+                action_horizon=10,
+                max_token_len=100,
+            ),
+            data=RLDSDroidDataConfig(
+                assets=AssetsConfig(
+                    assets_dir="gs://openpi-assets/checkpoints/polaris/pi0_droid_jointpos_100k_polaris/assets",
+                    asset_id="droid",
+                ),
+                datasets=(
+                    droid_rlds_dataset.RLDSDataset(
+                        name="droid",
+                        version="1.0.1",
+                        weight=0.9,
+                        filter_dict_path="gs://openpi-assets/droid/droid_sample_ranges_v1_0_1.json",
+                    ),
+                    droid_rlds_dataset.RLDSDataset(
+                        name="polaris_droid_cotrain_dataset",
+                        version="1.0.0",
+                        weight=0.1,
+                        filter_dict_path="gs://openpi-assets/droid/polaris_droid_cotrain_dataset_sample_ranges_v1_0_0.json",
+                    ),
+                ),
+                rlds_data_dir="<path_to_droid_rlds_dataset>",
+                action_space=droid_rlds_dataset.DroidActionSpace.JOINT_POSITION,
+            ),
+            weight_loader=weight_loaders.CheckpointWeightLoader(
+                "gs://openpi-assets/checkpoints/polaris/pi0_droid_jointpos_100k_polaris/params"
+            ),
+            lr_schedule=_optimizer.CosineDecaySchedule(
+                warmup_steps=1_000,
+                peak_lr=5e-5,
+                decay_steps=1_000_000,
+                decay_lr=5e-5,
+            ),
+            num_train_steps=1_000,
+            batch_size=128,
+            log_interval=100,
+            save_interval=1000,
+            keep_period=1000,
+            num_workers=0,  # Important: RLDS DataLoader requires num_workers=0, handles multi-processing internally
+        ),
+        # openpi doesn't support finetuning of binning policies, so this is an inference-only config
+        TrainConfig(
+            name="paligemma_binning_droid_jointpos",
+            model=pi0_fast.Pi0FASTConfig(
+                action_dim=8,
+                action_horizon=15,
+                max_token_len=600,
+                fast_model_tokenizer=_tokenizer.BinningTokenizer,
+            ),
+            data=SimpleDataConfig(
+                assets=AssetsConfig(asset_id="droid"),
+                data_transforms=lambda model: _transforms.Group(
+                    inputs=[droid_policy.DroidInputs(model_type=ModelType.PI0_FAST)],
+                    outputs=[
+                        _transforms.AbsoluteActions(_transforms.make_bool_mask(7, -1)),
+                        droid_policy.DroidOutputs(),
+                    ],
+                ),
+            ),
+        ),
+    ]
diff --git a/openpi_runtime/openpi/training/misc/roboarena_config.py b/openpi_runtime/openpi/training/misc/roboarena_config.py
new file mode 100644
index 0000000000000000000000000000000000000000..0795bae87be86fc463298cfb008ab393e037353d
--- /dev/null
+++ b/openpi_runtime/openpi/training/misc/roboarena_config.py
@@ -0,0 +1,116 @@
+"""RoboArena baseline policy configs."""
+
+from typing import TypeAlias
+
+import openpi.models.model as _model
+import openpi.models.pi0_config as pi0_config
+import openpi.models.pi0_fast as pi0_fast
+import openpi.models.tokenizer as _tokenizer
+import openpi.policies.droid_policy as droid_policy
+import openpi.transforms as _transforms
+
+ModelType: TypeAlias = _model.ModelType
+
+
+def get_roboarena_configs():
+    # Import here to avoid circular imports.
+    from openpi.training.config import AssetsConfig
+    from openpi.training.config import DataConfig
+    from openpi.training.config import SimpleDataConfig
+    from openpi.training.config import TrainConfig
+
+    return [
+        #
+        # RoboArena DROID baseline inference configs.
+        #
+        TrainConfig(
+            # Trained from PaliGemma, using RT-2 / OpenVLA style binning tokenizer.
+            name="paligemma_binning_droid",
+            model=pi0_fast.Pi0FASTConfig(
+                action_dim=8,
+                action_horizon=15,
+                max_token_len=400,
+                fast_model_tokenizer=_tokenizer.BinningTokenizer,
+            ),
+            data=SimpleDataConfig(
+                assets=AssetsConfig(asset_id="droid"),
+                data_transforms=lambda model: _transforms.Group(
+                    inputs=[droid_policy.DroidInputs(action_dim=model.action_dim, model_type=ModelType.PI0_FAST)],
+                    outputs=[droid_policy.DroidOutputs()],
+                ),
+                base_config=DataConfig(
+                    prompt_from_task=True,
+                ),
+            ),
+        ),
+        TrainConfig(
+            # Trained from PaliGemma, using FAST tokenizer (using universal FAST+ tokenizer).
+            name="paligemma_fast_droid",
+            model=pi0_fast.Pi0FASTConfig(action_dim=8, action_horizon=15),
+            data=SimpleDataConfig(
+                assets=AssetsConfig(asset_id="droid"),
+                data_transforms=lambda model: _transforms.Group(
+                    inputs=[droid_policy.DroidInputs(action_dim=model.action_dim, model_type=ModelType.PI0_FAST)],
+                    outputs=[droid_policy.DroidOutputs()],
+                ),
+                base_config=DataConfig(
+                    prompt_from_task=True,
+                ),
+            ),
+        ),
+        TrainConfig(
+            # Trained from PaliGemma, using FAST tokenizer (tokenizer trained on DROID dataset).
+            name="paligemma_fast_specialist_droid",
+            model=pi0_fast.Pi0FASTConfig(
+                action_dim=8,
+                action_horizon=15,
+                fast_model_tokenizer=_tokenizer.FASTTokenizer,
+                fast_model_tokenizer_kwargs={"fast_tokenizer_path": "KarlP/fast_droid_specialist"},
+            ),
+            data=SimpleDataConfig(
+                assets=AssetsConfig(asset_id="droid"),
+                data_transforms=lambda model: _transforms.Group(
+                    inputs=[droid_policy.DroidInputs(action_dim=model.action_dim, model_type=ModelType.PI0_FAST)],
+                    outputs=[droid_policy.DroidOutputs()],
+                ),
+                base_config=DataConfig(
+                    prompt_from_task=True,
+                ),
+            ),
+        ),
+        TrainConfig(
+            # Trained from PaliGemma, using FSQ tokenizer.
+            name="paligemma_vq_droid",
+            model=pi0_fast.Pi0FASTConfig(
+                action_dim=8,
+                action_horizon=15,
+                fast_model_tokenizer=_tokenizer.FSQTokenizer,
+                fast_model_tokenizer_kwargs={"fsq_tokenizer_path": "gs://openpi-assets/tokenizers/droid_fsq_tokenizer"},
+            ),
+            data=SimpleDataConfig(
+                assets=AssetsConfig(asset_id="droid"),
+                data_transforms=lambda model: _transforms.Group(
+                    inputs=[droid_policy.DroidInputs(action_dim=model.action_dim, model_type=ModelType.PI0_FAST)],
+                    outputs=[droid_policy.DroidOutputs()],
+                ),
+                base_config=DataConfig(
+                    prompt_from_task=True,
+                ),
+            ),
+        ),
+        TrainConfig(
+            # pi0-style diffusion / flow VLA, trained on DROID from PaliGemma.
+            name="paligemma_diffusion_droid",
+            model=pi0_config.Pi0Config(action_horizon=10, action_dim=8),
+            data=SimpleDataConfig(
+                assets=AssetsConfig(asset_id="droid"),
+                data_transforms=lambda model: _transforms.Group(
+                    inputs=[droid_policy.DroidInputs(action_dim=model.action_dim)],
+                    outputs=[droid_policy.DroidOutputs()],
+                ),
+                base_config=DataConfig(
+                    prompt_from_task=True,
+                ),
+            ),
+        ),
+    ]
diff --git a/openpi_runtime/openpi/training/optimizer.py b/openpi_runtime/openpi/training/optimizer.py
new file mode 100644
index 0000000000000000000000000000000000000000..1d1cc9d7e53656f671468054be45f09b97529b96
--- /dev/null
+++ b/openpi_runtime/openpi/training/optimizer.py
@@ -0,0 +1,109 @@
+import dataclasses
+from typing import Protocol, runtime_checkable
+
+import jax.numpy as jnp
+import optax
+
+import openpi.shared.array_typing as at
+
+
+@runtime_checkable
+class LRScheduleConfig(Protocol):
+    def create(self) -> optax.Schedule: ...
+
+
+@dataclasses.dataclass(frozen=True)
+class CosineDecaySchedule(LRScheduleConfig):
+    """Cosine decay schedule with warmup."""
+
+    warmup_steps: int = 1_000
+    peak_lr: float = 2.5e-5
+    decay_steps: int = 30_000
+    decay_lr: float = 2.5e-6
+
+    def create(self) -> optax.Schedule:
+        return optax.warmup_cosine_decay_schedule(
+            init_value=self.peak_lr / (self.warmup_steps + 1),
+            peak_value=self.peak_lr,
+            warmup_steps=self.warmup_steps,
+            decay_steps=self.decay_steps,
+            end_value=self.decay_lr,
+        )
+
+
+@dataclasses.dataclass(frozen=True)
+class RsqrtDecaySchedule(LRScheduleConfig):
+    """Inverse square root decay schedule with warmup."""
+
+    warmup_steps: int = 1_000
+    peak_lr: float = 5e-5
+    timescale: float = 10_000
+
+    def create(self) -> optax.Schedule:
+        return optax.join_schedules(
+            [
+                optax.linear_schedule(
+                    init_value=self.peak_lr / (self.warmup_steps + 1),
+                    end_value=self.peak_lr,
+                    transition_steps=self.warmup_steps,
+                ),
+                lambda step: self.peak_lr / jnp.sqrt((self.timescale + step) / self.timescale),
+            ],
+            [self.warmup_steps],
+        )
+
+
+@runtime_checkable
+class OptimizerConfig(Protocol):
+    def create(
+        self,
+        lr: optax.ScalarOrSchedule,
+        weight_decay_mask: at.PyTree | None = None,
+    ) -> optax.GradientTransformation: ...
+
+
+@dataclasses.dataclass(frozen=True)
+class AdamW(OptimizerConfig):
+    """AdamW optimizer."""
+
+    b1: float = 0.9
+    b2: float = 0.95
+    eps: float = 1e-8
+    # Changing this to 0 can cause out-of-memory errors for some reason, so we set it to a negligible value.
+    weight_decay: float = 1e-10
+    clip_gradient_norm: float = 1.0
+
+    def create(
+        self,
+        lr: optax.ScalarOrSchedule,
+        weight_decay_mask: at.PyTree | None = None,
+    ) -> optax.GradientTransformation:
+        tx = optax.adamw(
+            lr, b1=self.b1, b2=self.b2, eps=self.eps, weight_decay=self.weight_decay, mask=weight_decay_mask
+        )
+
+        return optax.chain(optax.clip_by_global_norm(self.clip_gradient_norm), tx)
+
+
+@dataclasses.dataclass(frozen=True)
+class SGD(OptimizerConfig):
+    """SGD optimizer."""
+
+    lr: float = 5e-5
+    momentum: float = 0.9
+    nesterov: bool = False
+
+    def create(
+        self,
+        lr: optax.ScalarOrSchedule,
+        weight_decay_mask: at.PyTree | None = None,
+    ) -> optax.GradientTransformation:
+        assert weight_decay_mask is None, "Weight decay is not supported for SGD"
+        return optax.sgd(lr, momentum=self.momentum, nesterov=self.nesterov)
+
+
+def create_optimizer(
+    optimizer: OptimizerConfig, lr_schedule: LRScheduleConfig, weight_decay_mask: at.PyTree | None = None
+) -> optax.GradientTransformation:
+    lr = lr_schedule.create()
+    return optimizer.create(lr, weight_decay_mask=weight_decay_mask)
diff --git a/openpi_runtime/openpi/training/sharding.py b/openpi_runtime/openpi/training/sharding.py
new file mode 100644
index 0000000000000000000000000000000000000000..344c5509bea53fb8e9352279a2df9930baa09d8c
--- /dev/null
+++ b/openpi_runtime/openpi/training/sharding.py
@@ -0,0 +1,102 @@
+import contextlib
+import logging
+
+import jax
+import numpy as np
+
+BATCH_AXIS = "batch"
+FSDP_AXIS = "fsdp"
+# In FSDP, we shard the data across both the batch and FSDP axes.
+DATA_AXIS = (BATCH_AXIS, FSDP_AXIS)
+
+
+class _MeshState:
+    active_mesh: jax.sharding.Mesh | None = None
+
+
+def make_mesh(num_fsdp_devices: int) -> jax.sharding.Mesh:
+    if jax.device_count() % num_fsdp_devices != 0:
+        raise ValueError(
+            f"Number of devices {jax.device_count()} must be divisible by the number of FSDP devices {num_fsdp_devices}."
+        )
+    mesh_shape = (jax.device_count() // num_fsdp_devices, num_fsdp_devices)
+    return jax.make_mesh(mesh_shape, (BATCH_AXIS, FSDP_AXIS))
+
+
+@contextlib.contextmanager
+def set_mesh(mesh: jax.sharding.Mesh):
+    """Plumbing the mesh deep into the module tree is extremely cumbersome; until the JAX team lands a better API, a
+    custom context manager like this one is the recommended way to maintain a reference to a global mesh. This is only used
+    in `activation_sharding_constraint` below."""
+    if _MeshState.active_mesh is not None:
+        raise ValueError("Cannot nest set_mesh context managers.")
+    _MeshState.active_mesh = mesh
+    try:
+        yield
+    finally:
+        _MeshState.active_mesh = None
+
+
+def activation_sharding_constraint(pytree):
+    if _MeshState.active_mesh is None:
+        return pytree
+    return jax.lax.with_sharding_constraint(
+        pytree, jax.sharding.NamedSharding(_MeshState.active_mesh, jax.sharding.PartitionSpec(DATA_AXIS))
+    )
+
+
+def fsdp_sharding(
+    pytree,
+    mesh: jax.sharding.Mesh,
+    *,
+    min_size_mbytes: int = 4,  # 4 MiB
+    log: bool = False,
+):
+    """Apply FSDP sharding to a pytree of arrays based on the mesh shape.
+
+    Args:
+        pytree: A pytree to be apply sharding specified by the mesh, note that only array types (eg. contains .shape attr)
+          will be considered for sharding.
+        mesh: The mesh being used for applying sharding on to pytree.
+        min_size_mbytes: The minimum size of the array in MiB to be considered for sharding, any array smaller than this
+          will be replicated.
+        log: If true, will log the sharding decisions for arrays that are being considered for sharding.
+
+    Returns:
+        The sharded pytree.
+    """
+    min_size_bytes = min_size_mbytes * 2**20
+
+    def _shard_arr(kp, array: jax.ShapeDtypeStruct):
+        # if fsdp is not actually going to be used, replicate everything to avoid extraneous logging
+        if mesh.shape[FSDP_AXIS] == 1:
+            return jax.sharding.NamedSharding(mesh, jax.sharding.PartitionSpec())
+        # replicate scalar and vector arrays
+        if not hasattr(array, "shape"):
+            return jax.sharding.NamedSharding(mesh, jax.sharding.PartitionSpec())
+        if len(array.shape) < 2:
+            return jax.sharding.NamedSharding(mesh, jax.sharding.PartitionSpec())
+        # replicate small arrays
+        if (arr_size := np.prod(array.shape) * np.dtype(array.dtype).itemsize) < min_size_bytes:
+            return jax.sharding.NamedSharding(mesh, jax.sharding.PartitionSpec())
+
+        # shard matrices and larger tensors along the largest axis that is divisible by the fsdp dimension
+        axes = np.argsort(array.shape)[::-1]
+        spec = [None] * len(axes)
+        for i in axes:
+            if array.shape[i] % mesh.shape[FSDP_AXIS] == 0:
+                if log:
+                    logging.info(
+                        f"Sharding {jax.tree_util.keystr(kp)} of shape {array.shape} ({arr_size / 2**20:.2f} MiB) along axis {i}"
+                    )
+                spec[i] = FSDP_AXIS
+                return jax.sharding.NamedSharding(mesh, jax.sharding.PartitionSpec(*spec))
+
+        # replicate if no valid sharding was found
+        if log:
+            logging.warning(
+                f"Could not find a valid sharding for {jax.tree_util.keystr(kp)} of shape {array.shape} with mesh of shape {mesh.shape}"
+            )
+        return jax.sharding.NamedSharding(mesh, jax.sharding.PartitionSpec())
+
+    return jax.tree_util.tree_map_with_path(_shard_arr, pytree)
diff --git a/openpi_runtime/openpi/training/utils.py b/openpi_runtime/openpi/training/utils.py
new file mode 100644
index 0000000000000000000000000000000000000000..fe7f94db1843b4b817cf24a007ca0b400946a066
--- /dev/null
+++ b/openpi_runtime/openpi/training/utils.py
@@ -0,0 +1,38 @@
+from collections.abc import Callable
+from typing import Any
+
+from flax import nnx
+from flax import struct
+import jax
+import optax
+
+from openpi.models import model as _model
+from openpi.shared import array_typing as at
+
+
+@at.typecheck
+@struct.dataclass
+class TrainState:
+    step: at.Int[at.ArrayLike, ""]
+    params: nnx.State
+    model_def: nnx.GraphDef[_model.BaseModel]
+    opt_state: optax.OptState
+    tx: optax.GradientTransformation = struct.field(pytree_node=False)
+
+    ema_decay: float | None = struct.field(pytree_node=False)
+    ema_params: nnx.State | None = None
+
+
+@at.typecheck
+def tree_to_info(tree: at.PyTree, interp_func: Callable[[Any], str] = str) -> str:
+    """Converts a PyTree into a human-readable string for logging. Optionally, `interp_func` can be provided to convert
+    the leaf values to more meaningful strings.
+    """
+    tree, _ = jax.tree_util.tree_flatten_with_path(tree)
+    return "\n".join(f"{jax.tree_util.keystr(path)}: {interp_func(value)}" for path, value in tree)
+
+
+@at.typecheck
+def array_tree_to_info(tree: at.PyTree) -> str:
+    """Converts a PyTree of arrays into a human-readable string for logging."""
+    return tree_to_info(tree, lambda x: f"{x.shape}@{x.dtype}")
diff --git a/openpi_runtime/openpi/training/weight_loaders.py b/openpi_runtime/openpi/training/weight_loaders.py
new file mode 100644
index 0000000000000000000000000000000000000000..0eee1c61d4dba0cb12f7907a319d746a106e7d86
--- /dev/null
+++ b/openpi_runtime/openpi/training/weight_loaders.py
@@ -0,0 +1,104 @@
+import dataclasses
+import logging
+import re
+from typing import Protocol, runtime_checkable
+
+import flax.traverse_util
+import numpy as np
+
+import openpi.models.model as _model
+import openpi.shared.array_typing as at
+import openpi.shared.download as download
+
+logger = logging.getLogger(__name__)
+
+
+@runtime_checkable
+class WeightLoader(Protocol):
+    def load(self, params: at.Params) -> at.Params:
+        """Loads the model weights.
+
+        Args:
+            params: Parameters of the model. This is a nested structure of array-like objects that
+                represent the model's parameters.
+
+        Returns:
+            Loaded parameters. The structure must be identical to `params`. If returning a subset of
+            the parameters the loader must merge the loaded parameters with `params`.
+        """
+
+
+@dataclasses.dataclass(frozen=True)
+class NoOpWeightLoader(WeightLoader):
+    def load(self, params: at.Params) -> at.Params:
+        return params
+
+
+@dataclasses.dataclass(frozen=True)
+class CheckpointWeightLoader(WeightLoader):
+    """Loads an entire set of weights from a checkpoint.
+
+    Compatible with:
+      trained checkpoints:
+        example: "./checkpoints/<config>/<exp>/<step>/params"
+      released checkpoints:
+        example: "gs://openpi-assets/checkpoints/<model>/params"
+    """
+
+    params_path: str
+
+    def load(self, params: at.Params) -> at.Params:
+        # We are loading np.ndarray and relying on the training code to properly convert and shard the params.
+        loaded_params = _model.restore_params(download.maybe_download(self.params_path), restore_type=np.ndarray)
+        # Add all missing LoRA weights.
+        return _merge_params(loaded_params, params, missing_regex=".*lora.*")
+
+
+@dataclasses.dataclass(frozen=True)
+class PaliGemmaWeightLoader(WeightLoader):
+    """Loads weights from the official PaliGemma checkpoint.
+
+    This will overwrite existing weights with similar names while keeping all extra weights intact.
+    This allows us to support the action expert which is used by the Pi0 model.
+    """
+
+    def load(self, params: at.Params) -> at.Params:
+        path = download.maybe_download(
+            "gs://vertex-model-garden-paligemma-us/paligemma/pt_224.npz", gs={"token": "anon"}
+        )
+        with path.open("rb") as f:
+            flat_params = dict(np.load(f, allow_pickle=False))
+        loaded_params = {"PaliGemma": flax.traverse_util.unflatten_dict(flat_params, sep="/")["params"]}
+        # Add all missing weights.
+        return _merge_params(loaded_params, params, missing_regex=".*")
+
+
+def _merge_params(loaded_params: at.Params, params: at.Params, *, missing_regex: str) -> at.Params:
+    """Merges the loaded parameters with the reference parameters.
+
+    Args:
+        loaded_params: The parameters to merge.
+        params: The reference parameters.
+        missing_regex: A regex pattern for all missing keys that should be merged from the reference parameters.
+
+    Returns:
+        A new dictionary with the merged parameters.
+    """
+    flat_ref = flax.traverse_util.flatten_dict(params, sep="/")
+    flat_loaded = flax.traverse_util.flatten_dict(loaded_params, sep="/")
+
+    # First, take all weights that are a subset of the reference weights.
+    result = {}
+    for k, v in flat_loaded.items():
+        if k in flat_ref:
+            result[k] = v.astype(flat_ref[k].dtype) if v.dtype != flat_ref[k].dtype else v
+
+    flat_loaded.clear()
+
+    # Then, merge any missing weights as defined by the missing regex.
+    pattern = re.compile(missing_regex)
+    for k in {k for k in flat_ref if pattern.fullmatch(k)}:
+        if k not in result:
+            result[k] = flat_ref[k]
+
+    return flax.traverse_util.unflatten_dict(result, sep="/")
diff --git a/openpi_runtime/openpi/transforms.py b/openpi_runtime/openpi/transforms.py
new file mode 100644
index 0000000000000000000000000000000000000000..272375ea95a5e43a42a6c0ff14cf89d34da76a45
--- /dev/null
+++ b/openpi_runtime/openpi/transforms.py
@@ -0,0 +1,460 @@
+from collections.abc import Callable, Mapping, Sequence
+import dataclasses
+import re
+from typing import Protocol, TypeAlias, TypeVar, runtime_checkable
+
+import flax.traverse_util as traverse_util
+import jax
+import numpy as np
+from openpi_client import image_tools
+
+from openpi.models import tokenizer as _tokenizer
+from openpi.shared import array_typing as at
+from openpi.shared import normalize as _normalize
+
+DataDict: TypeAlias = at.PyTree
+NormStats: TypeAlias = _normalize.NormStats
+
+
+T = TypeVar("T")
+S = TypeVar("S")
+
+
+@runtime_checkable
+class DataTransformFn(Protocol):
+    def __call__(self, data: DataDict) -> DataDict:
+        """Apply transformation to the data.
+
+        Args:
+            data: The data to apply the transform to. This is a possibly nested dictionary that contains
+                unbatched data elements. Each leaf is expected to be a numpy array. Using JAX arrays is allowed
+                but not recommended since it may result in extra GPU memory usage inside data loader worker
+                processes.
+
+        Returns:
+            The transformed data. Could be the input `data` that was modified in place, or a new data structure.
+        """
+
+
+@dataclasses.dataclass(frozen=True)
+class Group:
+    """A group of transforms."""
+
+    # Transforms that are applied to the model input data.
+    inputs: Sequence[DataTransformFn] = ()
+
+    # Transforms that are applied to the model output data.
+    outputs: Sequence[DataTransformFn] = ()
+
+    def push(self, *, inputs: Sequence[DataTransformFn] = (), outputs: Sequence[DataTransformFn] = ()) -> "Group":
+        """Append transforms to the group and return a new group.
+
+        Args:
+            inputs: Appended to the *end* of the current input transforms.
+            outputs: Appended to the *beginning* of the current output transforms.
+
+        Returns:
+            A new group with the appended transforms.
+        """
+        return Group(inputs=(*self.inputs, *inputs), outputs=(*outputs, *self.outputs))
+
+
+@dataclasses.dataclass(frozen=True)
+class CompositeTransform(DataTransformFn):
+    """A composite transform that applies a sequence of transforms in order."""
+
+    transforms: Sequence[DataTransformFn]
+
+    def __call__(self, data: DataDict) -> DataDict:
+        for transform in self.transforms:
+            data = transform(data)
+        return data
+
+
+def compose(transforms: Sequence[DataTransformFn]) -> DataTransformFn:
+    """Compose a sequence of transforms into a single transform."""
+    return CompositeTransform(transforms)
+
+
+@dataclasses.dataclass(frozen=True)
+class RepackTransform(DataTransformFn):
+    """Repacks an input dictionary into a new dictionary.
+
+    Repacking is defined using a dictionary where the keys are the new keys and the values
+    are the flattened paths to the old keys. We use '/' as the separator during flattening.
+
+    Example:
+    {
+        "images": {
+            "cam_high": "observation.images.top",
+            "cam_low": "observation.images.bottom",
+        },
+        "state": "observation.state",
+        "actions": "action",
+    }
+    """
+
+    structure: at.PyTree[str]
+
+    def __call__(self, data: DataDict) -> DataDict:
+        flat_item = flatten_dict(data)
+        return jax.tree.map(lambda k: flat_item[k], self.structure)
+
+
+@dataclasses.dataclass(frozen=True)
+class InjectDefaultPrompt(DataTransformFn):
+    prompt: str | None
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if self.prompt is not None and "prompt" not in data:
+            data["prompt"] = np.asarray(self.prompt)
+        return data
+
+
+@dataclasses.dataclass(frozen=True)
+class Normalize(DataTransformFn):
+    norm_stats: at.PyTree[NormStats] | None
+    # If true, will use quantile normalization. Otherwise, normal z-score normalization will be used.
+    use_quantiles: bool = False
+    # If true, will raise an error if any of the keys in the norm stats are not present in the data.
+    strict: bool = False
+
+    def __post_init__(self):
+        if self.norm_stats is not None and self.use_quantiles:
+            _assert_quantile_stats(self.norm_stats)
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if self.norm_stats is None:
+            return data
+
+        return apply_tree(
+            data,
+            self.norm_stats,
+            self._normalize_quantile if self.use_quantiles else self._normalize,
+            strict=self.strict,
+        )
+
+    def _normalize(self, x, stats: NormStats):
+        mean, std = stats.mean[..., : x.shape[-1]], stats.std[..., : x.shape[-1]]
+        return (x - mean) / (std + 1e-6)
+
+    def _normalize_quantile(self, x, stats: NormStats):
+        assert stats.q01 is not None
+        assert stats.q99 is not None
+        q01, q99 = stats.q01[..., : x.shape[-1]], stats.q99[..., : x.shape[-1]]
+        return (x - q01) / (q99 - q01 + 1e-6) * 2.0 - 1.0
+
+
+@dataclasses.dataclass(frozen=True)
+class Unnormalize(DataTransformFn):
+    norm_stats: at.PyTree[NormStats] | None
+    # If true, will use quantile normalization. Otherwise, normal z-score normalization will be used.
+    use_quantiles: bool = False
+
+    def __post_init__(self):
+        if self.norm_stats is not None and self.use_quantiles:
+            _assert_quantile_stats(self.norm_stats)
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if self.norm_stats is None:
+            return data
+
+        # Make sure that all the keys in the norm stats are present in the data.
+        return apply_tree(
+            data,
+            self.norm_stats,
+            self._unnormalize_quantile if self.use_quantiles else self._unnormalize,
+            strict=True,
+        )
+
+    def _unnormalize(self, x, stats: NormStats):
+        mean = pad_to_dim(stats.mean, x.shape[-1], axis=-1, value=0.0)
+        std = pad_to_dim(stats.std, x.shape[-1], axis=-1, value=1.0)
+        return x * (std + 1e-6) + mean
+
+    def _unnormalize_quantile(self, x, stats: NormStats):
+        assert stats.q01 is not None
+        assert stats.q99 is not None
+        q01, q99 = stats.q01, stats.q99
+        if (dim := q01.shape[-1]) < x.shape[-1]:
+            return np.concatenate([(x[..., :dim] + 1.0) / 2.0 * (q99 - q01 + 1e-6) + q01, x[..., dim:]], axis=-1)
+        return (x + 1.0) / 2.0 * (q99 - q01 + 1e-6) + q01
+
+
+@dataclasses.dataclass(frozen=True)
+class ResizeImages(DataTransformFn):
+    height: int
+    width: int
+
+    def __call__(self, data: DataDict) -> DataDict:
+        data["image"] = {k: image_tools.resize_with_pad(v, self.height, self.width) for k, v in data["image"].items()}
+        return data
+
+
+@dataclasses.dataclass(frozen=True)
+class SubsampleActions(DataTransformFn):
+    stride: int
+
+    def __call__(self, data: DataDict) -> DataDict:
+        data["actions"] = data["actions"][:: self.stride]
+        return data
+
+
+@dataclasses.dataclass(frozen=True)
+class DeltaActions(DataTransformFn):
+    """Repacks absolute actions into delta action space."""
+
+    # Boolean mask for the action dimensions to be repacked into delta action space. Length
+    # can be smaller than the actual number of dimensions. If None, this transform is a no-op.
+    # See `make_bool_mask` for more details.
+    mask: Sequence[bool] | None
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if "actions" not in data or self.mask is None:
+            return data
+
+        state, actions = data["state"], data["actions"]
+        mask = np.asarray(self.mask)
+        dims = mask.shape[-1]
+        actions[..., :dims] -= np.expand_dims(np.where(mask, state[..., :dims], 0), axis=-2)
+        data["actions"] = actions
+
+        return data
+
+
+@dataclasses.dataclass(frozen=True)
+class AbsoluteActions(DataTransformFn):
+    """Repacks delta actions into absolute action space."""
+
+    # Boolean mask for the action dimensions to be repacked into absolute action space. Length
+    # can be smaller than the actual number of dimensions. If None, this transform is a no-op.
+    # See `make_bool_mask` for more details.
+    mask: Sequence[bool] | None
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if "actions" not in data or self.mask is None:
+            return data
+
+        state, actions = data["state"], data["actions"]
+        mask = np.asarray(self.mask)
+        dims = mask.shape[-1]
+        actions[..., :dims] += np.expand_dims(np.where(mask, state[..., :dims], 0), axis=-2)
+        data["actions"] = actions
+
+        return data
+
+
+@dataclasses.dataclass(frozen=True)
+class TokenizePrompt(DataTransformFn):
+    tokenizer: _tokenizer.PaligemmaTokenizer
+    discrete_state_input: bool = False
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if (prompt := data.pop("prompt", None)) is None:
+            raise ValueError("Prompt is required")
+
+        if self.discrete_state_input:
+            if (state := data.get("state", None)) is None:
+                raise ValueError("State is required.")
+        else:
+            state = None
+
+        if not isinstance(prompt, str):
+            prompt = prompt.item()
+
+        tokens, token_masks = self.tokenizer.tokenize(prompt, state)
+        return {**data, "tokenized_prompt": tokens, "tokenized_prompt_mask": token_masks}
+
+
+@dataclasses.dataclass(frozen=True)
+class TokenizeFASTInputs(DataTransformFn):
+    tokenizer: _tokenizer.FASTTokenizer
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if (prompt := data.pop("prompt", None)) is None:
+            raise ValueError("Prompt is required")
+
+        if not isinstance(prompt, str):
+            prompt = prompt.item()
+
+        state, actions = data["state"], data.get("actions")
+        tokens, token_mask, ar_mask, loss_mask = self.tokenizer.tokenize(prompt, state, actions)
+        return {
+            **data,
+            "tokenized_prompt": tokens,
+            "tokenized_prompt_mask": token_mask,
+            "token_ar_mask": ar_mask,
+            "token_loss_mask": loss_mask,
+        }
+
+
+@dataclasses.dataclass(frozen=True)
+class ExtractFASTActions(DataTransformFn):
+    tokenizer: _tokenizer.FASTTokenizer
+    action_horizon: int
+    action_dim: int
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if "actions" not in data:
+            return data
+        # Model outputs are saved in "actions", but for FAST models they represent tokens.
+        tokens = data.pop("actions")
+        actions = self.tokenizer.extract_actions(tokens.astype(np.int32), self.action_horizon, self.action_dim)
+        return {
+            **data,
+            "actions": actions,
+        }
+
+
+@dataclasses.dataclass(frozen=True)
+class PromptFromLeRobotTask(DataTransformFn):
+    """Extracts a prompt from the current LeRobot dataset task."""
+
+    # Contains the LeRobot dataset tasks (dataset.meta.tasks).
+    tasks: dict[int, str]
+
+    def __call__(self, data: DataDict) -> DataDict:
+        if "task_index" not in data:
+            raise ValueError('Cannot extract prompt without "task_index"')
+
+        task_index = int(data["task_index"])
+        if (prompt := self.tasks.get(task_index)) is None:
+            raise ValueError(f"{task_index=} not found in task mapping: {self.tasks}")
+
+        return {**data, "prompt": prompt}
+
+
+@dataclasses.dataclass(frozen=True)
+class PadStatesAndActions(DataTransformFn):
+    """Zero-pads states and actions to the model action dimension."""
+
+    model_action_dim: int
+
+    def __call__(self, data: DataDict) -> DataDict:
+        data["state"] = pad_to_dim(data["state"], self.model_action_dim, axis=-1)
+        if "actions" in data:
+            data["actions"] = pad_to_dim(data["actions"], self.model_action_dim, axis=-1)
+        return data
+
+
+def flatten_dict(tree: at.PyTree) -> dict:
+    """Flatten a nested dictionary. Uses '/' as the separator."""
+    return traverse_util.flatten_dict(tree, sep="/")
+
+
+def unflatten_dict(tree: dict) -> at.PyTree:
+    """Unflatten a flattened dictionary. Assumes that '/' was used as a separator."""
+    return traverse_util.unflatten_dict(tree, sep="/")
+
+
+def transform_dict(patterns: Mapping[str, str | None], tree: at.PyTree) -> at.PyTree:
+    """Transform the structure of a nested dictionary using a set of patterns.
+
+    The transformation is defined using the `patterns` dictionary. The keys are the
+    input keys that should be matched and the values are the new names inside the output
+    dictionary. If the value is None, the input key is removed.
+
+    Both keys and values should represent flattened paths using '/' as the separator.
+    Keys can be regular expressions and values can include backreferences to the
+    matched groups (see `re.sub` for more details). Note that the regular expression
+    must match the entire key.
+
+    The order inside the `patterns` dictionary is important. Only the first pattern that
+    matches the input key will be used.
+
+    See unit tests for more examples.
+
+    Args:
+        patterns: A mapping from old keys to new keys.
+        tree: The nested dictionary to transform.
+
+    Returns:
+        The transformed nested dictionary.
+    """
+    data = flatten_dict(tree)
+
+    # Compile the patterns.
+    compiled = {re.compile(k): v for k, v in patterns.items()}
+
+    output = {}
+    for k in data:
+        for pattern, repl in compiled.items():
+            if pattern.fullmatch(k):
+                new_k = pattern.sub(repl, k, count=1) if repl is not None else None
+                break
+        else:
+            # Use the original key if no match is found.
+            new_k = k
+
+        if new_k is not None:
+            if new_k in output:
+                raise ValueError(f"Key '{new_k}' already exists in output")
+            output[new_k] = data[k]
+
+    # Validate the output structure to make sure that it can be unflattened.
+    names = sorted(output)
+    for i in range(len(names) - 1):
+        name, next_name = names[i : i + 2]
+        if next_name.startswith(name + "/"):
+            raise ValueError(f"Leaf '{name}' aliases a node of '{next_name}'")
+
+    return unflatten_dict(output)
+
+
+def apply_tree(
+    tree: at.PyTree[T], selector: at.PyTree[S], fn: Callable[[T, S], T], *, strict: bool = False
+) -> at.PyTree[T]:
+    tree = flatten_dict(tree)
+    selector = flatten_dict(selector)
+
+    def transform(k: str, v: T) -> T:
+        if k in selector:
+            return fn(v, selector[k])
+        return v
+
+    if strict:
+        for k in selector:
+            if k not in tree:
+                raise ValueError(f"Selector key {k} not found in tree")
+
+    return unflatten_dict({k: transform(k, v) for k, v in tree.items()})
+
+
+def pad_to_dim(x: np.ndarray, target_dim: int, axis: int = -1, value: float = 0.0) -> np.ndarray:
+    """Pad an array to the target dimension with zeros along the specified axis."""
+    current_dim = x.shape[axis]
+    if current_dim < target_dim:
+        pad_width = [(0, 0)] * len(x.shape)
+        pad_width[axis] = (0, target_dim - current_dim)
+        return np.pad(x, pad_width, constant_values=value)
+    return x
+
+
+def make_bool_mask(*dims: int) -> tuple[bool, ...]:
+    """Make a boolean mask for the given dimensions.
+
+    Example:
+        make_bool_mask(2, -2, 2) == (True, True, False, False, True, True)
+        make_bool_mask(2, 0, 2) == (True, True, True, True)
+
+    Args:
+        dims: The dimensions to make the mask for.
+
+    Returns:
+        A tuple of booleans.
+    """
+    result = []
+    for dim in dims:
+        if dim > 0:
+            result.extend([True] * (dim))
+        else:
+            result.extend([False] * (-dim))
+    return tuple(result)
+
+
+def _assert_quantile_stats(norm_stats: at.PyTree[NormStats]) -> None:
+    for k, v in flatten_dict(norm_stats).items():
+        if v.q01 is None or v.q99 is None:
+            raise ValueError(
+                f"quantile stats must be provided if use_quantile_norm is True. Key {k} is missing q01 or q99."
+            )
diff --git a/openpi_runtime/openpi_client/__init__.py b/openpi_runtime/openpi_client/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..3dc1f76bc69e3f559bee6253b24fc93acee9e1f9
--- /dev/null
+++ b/openpi_runtime/openpi_client/__init__.py
@@ -0,0 +1 @@
+__version__ = "0.1.0"
diff --git a/openpi_runtime/openpi_client/action_chunk_broker.py b/openpi_runtime/openpi_client/action_chunk_broker.py
new file mode 100644
index 0000000000000000000000000000000000000000..8fa9d83d023b7c0c60a1d05531343af01e72d09b
--- /dev/null
+++ b/openpi_runtime/openpi_client/action_chunk_broker.py
@@ -0,0 +1,50 @@
+from typing import Dict
+
+import numpy as np
+import tree
+from typing_extensions import override
+
+from openpi_client import base_policy as _base_policy
+
+
+class ActionChunkBroker(_base_policy.BasePolicy):
+    """Wraps a policy to return action chunks one-at-a-time.
+
+    Assumes that the first dimension of all action fields is the chunk size.
+
+    A new inference call to the inner policy is only made when the current
+    list of chunks is exhausted.
+    """
+
+    def __init__(self, policy: _base_policy.BasePolicy, action_horizon: int):
+        self._policy = policy
+        self._action_horizon = action_horizon
+        self._cur_step: int = 0
+
+        self._last_results: Dict[str, np.ndarray] | None = None
+
+    @override
+    def infer(self, obs: Dict) -> Dict:  # noqa: UP006
+        if self._last_results is None:
+            self._last_results = self._policy.infer(obs)
+            self._cur_step = 0
+
+        def slicer(x):
+            if isinstance(x, np.ndarray):
+                return x[self._cur_step, ...]
+            else:
+                return x
+
+        results = tree.map_structure(slicer, self._last_results)
+        self._cur_step += 1
+
+        if self._cur_step >= self._action_horizon:
+            self._last_results = None
+
+        return results
+
+    @override
+    def reset(self) -> None:
+        self._policy.reset()
+        self._last_results = None
+        self._cur_step = 0
diff --git a/openpi_runtime/openpi_client/base_policy.py b/openpi_runtime/openpi_client/base_policy.py
new file mode 100644
index 0000000000000000000000000000000000000000..2f4290651b1b7bab3bd9549b47876838f5b51629
--- /dev/null
+++ b/openpi_runtime/openpi_client/base_policy.py
@@ -0,0 +1,12 @@
+import abc
+from typing import Dict
+
+
+class BasePolicy(abc.ABC):
+    @abc.abstractmethod
+    def infer(self, obs: Dict) -> Dict:
+        """Infer actions from observations."""
+
+    def reset(self) -> None:
+        """Reset the policy to its initial state."""
+        pass
diff --git a/openpi_runtime/openpi_client/image_tools.py b/openpi_runtime/openpi_client/image_tools.py
new file mode 100644
index 0000000000000000000000000000000000000000..7a971b9d5f6b1495fd6cdea202ffa607d8b34bf0
--- /dev/null
+++ b/openpi_runtime/openpi_client/image_tools.py
@@ -0,0 +1,58 @@
+import numpy as np
+from PIL import Image
+
+
+def convert_to_uint8(img: np.ndarray) -> np.ndarray:
+    """Converts an image to uint8 if it is a float image.
+
+    This is important for reducing the size of the image when sending it over the network.
+    """
+    if np.issubdtype(img.dtype, np.floating):
+        img = (255 * img).astype(np.uint8)
+    return img
+
+
+def resize_with_pad(images: np.ndarray, height: int, width: int, method=Image.BILINEAR) -> np.ndarray:
+    """Replicates tf.image.resize_with_pad for multiple images using PIL. Resizes a batch of images to a target height.
+
+    Args:
+        images: A batch of images in [..., height, width, channel] format.
+        height: The target height of the image.
+        width: The target width of the image.
+        method: The interpolation method to use. Default is bilinear.
+
+    Returns:
+        The resized images in [..., height, width, channel].
+    """
+    # If the images are already the correct size, return them as is.
+    if images.shape[-3:-1] == (height, width):
+        return images
+
+    original_shape = images.shape
+
+    images = images.reshape(-1, *original_shape[-3:])
+    resized = np.stack([_resize_with_pad_pil(Image.fromarray(im), height, width, method=method) for im in images])
+    return resized.reshape(*original_shape[:-3], *resized.shape[-3:])
+
+
+def _resize_with_pad_pil(image: Image.Image, height: int, width: int, method: int) -> Image.Image:
+    """Replicates tf.image.resize_with_pad for one image using PIL. Resizes an image to a target height and
+    width without distortion by padding with zeros.
+
+    Unlike the jax version, note that PIL uses [width, height, channel] ordering instead of [batch, h, w, c].
+    """
+    cur_width, cur_height = image.size
+    if cur_width == width and cur_height == height:
+        return image  # No need to resize if the image is already the correct size.
+
+    ratio = max(cur_width / width, cur_height / height)
+    resized_height = int(cur_height / ratio)
+    resized_width = int(cur_width / ratio)
+    resized_image = image.resize((resized_width, resized_height), resample=method)
+
+    zero_image = Image.new(resized_image.mode, (width, height), 0)
+    pad_height = max(0, int((height - resized_height) / 2))
+    pad_width = max(0, int((width - resized_width) / 2))
+    zero_image.paste(resized_image, (pad_width, pad_height))
+    assert zero_image.size == (width, height)
+    return zero_image
diff --git a/openpi_runtime/openpi_client/msgpack_numpy.py b/openpi_runtime/openpi_client/msgpack_numpy.py
new file mode 100644
index 0000000000000000000000000000000000000000..007f755edf54565579376b077eec7f7f715e1b96
--- /dev/null
+++ b/openpi_runtime/openpi_client/msgpack_numpy.py
@@ -0,0 +1,57 @@
+"""Adds NumPy array support to msgpack.
+
+msgpack is good for (de)serializing data over a network for multiple reasons:
+- msgpack is secure (as opposed to pickle/dill/etc which allow for arbitrary code execution)
+- msgpack is widely used and has good cross-language support
+- msgpack does not require a schema (as opposed to protobuf/flatbuffers/etc) which is convenient in dynamically typed
+    languages like Python and JavaScript
+- msgpack is fast and efficient (as opposed to readable formats like JSON/YAML/etc); I found that msgpack was ~4x faster
+    than pickle for serializing large arrays using the below strategy
+
+The code below is adapted from https://github.com/lebedov/msgpack-numpy. The reason not to use that library directly is
+that it falls back to pickle for object arrays.
+"""
+
+import functools
+
+import msgpack
+import numpy as np
+
+
+def pack_array(obj):
+    if (isinstance(obj, (np.ndarray, np.generic))) and obj.dtype.kind in ("V", "O", "c"):
+        raise ValueError(f"Unsupported dtype: {obj.dtype}")
+
+    if isinstance(obj, np.ndarray):
+        return {
+            b"__ndarray__": True,
+            b"data": obj.tobytes(),
+            b"dtype": obj.dtype.str,
+            b"shape": obj.shape,
+        }
+
+    if isinstance(obj, np.generic):
+        return {
+            b"__npgeneric__": True,
+            b"data": obj.item(),
+            b"dtype": obj.dtype.str,
+        }
+
+    return obj
+
+
+def unpack_array(obj):
+    if b"__ndarray__" in obj:
+        return np.ndarray(buffer=obj[b"data"], dtype=np.dtype(obj[b"dtype"]), shape=obj[b"shape"])
+
+    if b"__npgeneric__" in obj:
+        return np.dtype(obj[b"dtype"]).type(obj[b"data"])
+
+    return obj
+
+
+Packer = functools.partial(msgpack.Packer, default=pack_array)
+packb = functools.partial(msgpack.packb, default=pack_array)
+
+Unpacker = functools.partial(msgpack.Unpacker, object_hook=unpack_array)
+unpackb = functools.partial(msgpack.unpackb, object_hook=unpack_array)
diff --git a/openpi_runtime/openpi_client/runtime/agent.py b/openpi_runtime/openpi_client/runtime/agent.py
new file mode 100644
index 0000000000000000000000000000000000000000..a2c3ab66ef618ad9ecbff7b81ad9340a4604128c
--- /dev/null
+++ b/openpi_runtime/openpi_client/runtime/agent.py
@@ -0,0 +1,17 @@
+import abc
+
+
+class Agent(abc.ABC):
+    """An Agent is the thing with agency, i.e. the entity that makes decisions.
+
+    Agents receive observations about the state of the world, and return actions
+    to take in response.
+    """
+
+    @abc.abstractmethod
+    def get_action(self, observation: dict) -> dict:
+        """Query the agent for the next action."""
+
+    @abc.abstractmethod
+    def reset(self) -> None:
+        """Reset the agent to its initial state."""
diff --git a/openpi_runtime/openpi_client/runtime/agents/policy_agent.py b/openpi_runtime/openpi_client/runtime/agents/policy_agent.py
new file mode 100644
index 0000000000000000000000000000000000000000..65227c44dae667d9b2743b6bc1026e791cec35c4
--- /dev/null
+++ b/openpi_runtime/openpi_client/runtime/agents/policy_agent.py
@@ -0,0 +1,18 @@
+from typing_extensions import override
+
+from openpi_client import base_policy as _base_policy
+from openpi_client.runtime import agent as _agent
+
+
+class PolicyAgent(_agent.Agent):
+    """An agent that uses a policy to determine actions."""
+
+    def __init__(self, policy: _base_policy.BasePolicy) -> None:
+        self._policy = policy
+
+    @override
+    def get_action(self, observation: dict) -> dict:
+        return self._policy.infer(observation)
+
+    def reset(self) -> None:
+        self._policy.reset()
diff --git a/openpi_runtime/openpi_client/runtime/environment.py b/openpi_runtime/openpi_client/runtime/environment.py
new file mode 100644
index 0000000000000000000000000000000000000000..664ac4678aaaa3aecf52268a6a09d1d1fc974226
--- /dev/null
+++ b/openpi_runtime/openpi_client/runtime/environment.py
@@ -0,0 +1,32 @@
+import abc
+
+
+class Environment(abc.ABC):
+    """An Environment represents the robot and the environment it inhabits.
+
+    The primary contract of environments is that they can be queried for observations
+    about their state, and have actions applied to them to change that state.
+    """
+
+    @abc.abstractmethod
+    def reset(self) -> None:
+        """Reset the environment to its initial state.
+
+        This will be called once before starting each episode.
+        """
+
+    @abc.abstractmethod
+    def is_episode_complete(self) -> bool:
+        """Allow the environment to signal that the episode is complete.
+
+        This will be called after each step. It should return `True` if the episode is
+        complete (either successfully or unsuccessfully), and `False` otherwise.
+        """
+
+    @abc.abstractmethod
+    def get_observation(self) -> dict:
+        """Query the environment for the current state."""
+
+    @abc.abstractmethod
+    def apply_action(self, action: dict) -> None:
+        """Take an action in the environment."""
diff --git a/openpi_runtime/openpi_client/runtime/runtime.py b/openpi_runtime/openpi_client/runtime/runtime.py
new file mode 100644
index 0000000000000000000000000000000000000000..9552be091a26e163d60cab8071df4716524bf2e8
--- /dev/null
+++ b/openpi_runtime/openpi_client/runtime/runtime.py
@@ -0,0 +1,92 @@
+import logging
+import threading
+import time
+
+from openpi_client.runtime import agent as _agent
+from openpi_client.runtime import environment as _environment
+from openpi_client.runtime import subscriber as _subscriber
+
+
+class Runtime:
+    """The core module orchestrating interactions between key components of the system."""
+
+    def __init__(
+        self,
+        environment: _environment.Environment,
+        agent: _agent.Agent,
+        subscribers: list[_subscriber.Subscriber],
+        max_hz: float = 0,
+        num_episodes: int = 1,
+        max_episode_steps: int = 0,
+    ) -> None:
+        self._environment = environment
+        self._agent = agent
+        self._subscribers = subscribers
+        self._max_hz = max_hz
+        self._num_episodes = num_episodes
+        self._max_episode_steps = max_episode_steps
+
+        self._in_episode = False
+        self._episode_steps = 0
+
+    def run(self) -> None:
+        """Runs the runtime loop continuously until stop() is called or the environment is done."""
+        for _ in range(self._num_episodes):
+            self._run_episode()
+
+        # Final reset, this is important for real environments to move the robot to its home position.
+        self._environment.reset()
+
+    def run_in_new_thread(self) -> threading.Thread:
+        """Runs the runtime loop in a new thread."""
+        thread = threading.Thread(target=self.run)
+        thread.start()
+        return thread
+
+    def mark_episode_complete(self) -> None:
+        """Marks the end of an episode."""
+        self._in_episode = False
+
+    def _run_episode(self) -> None:
+        """Runs a single episode."""
+        logging.info("Starting episode...")
+        self._environment.reset()
+        self._agent.reset()
+        for subscriber in self._subscribers:
+            subscriber.on_episode_start()
+
+        self._in_episode = True
+        self._episode_steps = 0
+        step_time = 1 / self._max_hz if self._max_hz > 0 else 0
+        last_step_time = time.time()
+
+        while self._in_episode:
+            self._step()
+            self._episode_steps += 1
+
+            # Sleep to maintain the desired frame rate
+            now = time.time()
+            dt = now - last_step_time
+            if dt < step_time:
+                time.sleep(step_time - dt)
+                last_step_time = time.time()
+            else:
+                last_step_time = now
+
+        logging.info("Episode completed.")
+        for subscriber in self._subscribers:
+            subscriber.on_episode_end()
+
+    def _step(self) -> None:
+        """A single step of the runtime loop."""
+        observation = self._environment.get_observation()
+        action = self._agent.get_action(observation)
+        self._environment.apply_action(action)
+
+        for subscriber in self._subscribers:
+            subscriber.on_step(observation, action)
+
+        if self._environment.is_episode_complete() or (
+            self._max_episode_steps > 0 and self._episode_steps >= self._max_episode_steps
+        ):
+            self.mark_episode_complete()
diff --git a/openpi_runtime/openpi_client/runtime/subscriber.py b/openpi_runtime/openpi_client/runtime/subscriber.py
new file mode 100644
index 0000000000000000000000000000000000000000..7c69edaa8e814dfcfe56b78b774578fe37f79428
--- /dev/null
+++ b/openpi_runtime/openpi_client/runtime/subscriber.py
@@ -0,0 +1,20 @@
+import abc
+
+
+class Subscriber(abc.ABC):
+    """Subscribes to events in the runtime.
+
+    Subscribers can be used to save data, visualize, etc.
+    """
+
+    @abc.abstractmethod
+    def on_episode_start(self) -> None:
+        """Called when an episode starts."""
+
+    @abc.abstractmethod
+    def on_step(self, observation: dict, action: dict) -> None:
+        """Append a step to the episode."""
+
+    @abc.abstractmethod
+    def on_episode_end(self) -> None:
+        """Called when an episode ends."""
diff --git a/openpi_runtime/openpi_client/websocket_client_policy.py b/openpi_runtime/openpi_client/websocket_client_policy.py
new file mode 100644
index 0000000000000000000000000000000000000000..466685e00d004ff8c7dd5694636a8ec3e6439d11
--- /dev/null
+++ b/openpi_runtime/openpi_client/websocket_client_policy.py
@@ -0,0 +1,58 @@
+import logging
+import time
+from typing import Dict, Optional, Tuple
+
+from typing_extensions import override
+import websockets.sync.client
+
+from openpi_client import base_policy as _base_policy
+from openpi_client import msgpack_numpy
+
+
+class WebsocketClientPolicy(_base_policy.BasePolicy):
+    """Implements the Policy interface by communicating with a server over websocket.
+
+    See WebsocketPolicyServer for a corresponding server implementation.
+    """
+
+    def __init__(self, host: str = "0.0.0.0", port: Optional[int] = None, api_key: Optional[str] = None) -> None:
+        if host.startswith("ws"):
+            self._uri = host
+        else:
+            self._uri = f"ws://{host}"
+        if port is not None:
+            self._uri += f":{port}"
+        self._packer = msgpack_numpy.Packer()
+        self._api_key = api_key
+        self._ws, self._server_metadata = self._wait_for_server()
+
+    def get_server_metadata(self) -> Dict:
+        return self._server_metadata
+
+    def _wait_for_server(self) -> Tuple[websockets.sync.client.ClientConnection, Dict]:
+        logging.info(f"Waiting for server at {self._uri}...")
+        while True:
+            try:
+                headers = {"Authorization": f"Api-Key {self._api_key}"} if self._api_key else None
+                conn = websockets.sync.client.connect(
+                    self._uri, compression=None, max_size=None, additional_headers=headers
+                )
+                metadata = msgpack_numpy.unpackb(conn.recv())
+                return conn, metadata
+            except ConnectionRefusedError:
+                logging.info("Still waiting for server...")
+                time.sleep(5)
+
+    @override
+    def infer(self, obs: Dict) -> Dict:  # noqa: UP006
+        data = self._packer.pack(obs)
+        self._ws.send(data)
+        response = self._ws.recv()
+        if isinstance(response, str):
+            # we're expecting bytes; if the server sends a string, it's an error.
+            raise RuntimeError(f"Error in inference server:\n{response}")
+        return msgpack_numpy.unpackb(response)
+
+    @override
+    def reset(self) -> None:
+        pass
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000000000000000000000000000000000000..2c0fe4cb9b2833b15b42e6737a5532888e45d58b
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,30 @@
+gradio==6.20.0
+huggingface-hub==0.36.2
+pandas==2.2.3
+pillow==11.1.0
+numpy==1.26.4
+augmax>=0.3.4
+dm-tree>=0.1.8
+einops>=0.8.0
+equinox>=0.11.8
+flax==0.10.2
+fsspec[gcs]>=2024.6.0
+jax[cuda12]==0.5.3
+jaxtyping==0.2.36
+ml-collections==1.0.0
+numpydantic>=1.6.6
+opencv-python-headless>=4.10.0.84
+orbax-checkpoint==0.11.13
+sentencepiece>=0.2.0
+torch==2.7.1
+typing-extensions>=4.12.2
+tyro>=0.9.5
+wandb>=0.19.1
+filelock>=3.16.1
+beartype==0.19.0
+chex==0.1.90
+treescope>=0.1.7
+transformers==4.53.2
+rich>=14.0.0
+polars>=1.30.0
+pytest==8.3.5
diff --git a/tests/test_space_config.py b/tests/test_space_config.py
new file mode 100644
index 0000000000000000000000000000000000000000..0b9dec645896d9d284ac4b6068d0849c65dba967
--- /dev/null
+++ b/tests/test_space_config.py
@@ -0,0 +1,21 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).parents[1]
+
+
+def test_space_metadata_and_runtime_files():
+    readme = (ROOT / "README.md").read_text()
+    requirements = (ROOT / "requirements.txt").read_text()
+    assert "sdk_version: 6.20.0" in readme
+    assert "python_version: '3.11'" in readme
+    assert "app_file: app.py" in readme
+    assert "gradio==6.20.0" in requirements
+    assert (ROOT / "openpi_runtime/openpi/policies/ur_policy.py").is_file()
+    assert (ROOT / "openpi_runtime/openpi_client/base_policy.py").is_file()
+
+
+def test_vendored_config_contains_state_conditioned_ur_policy():
+    source = (ROOT / "openpi_runtime/openpi/training/config.py").read_text()
+    assert 'name="pi05_ur_demo_state"' in source
+    assert "LeRobotURDataConfig" in source