# How to use ONNX Runtime for inference
🤗 [Optimum](https://github.com/huggingface/optimum) provides a Stable Diffusion pipeline compatible with ONNX Runtime.
## Installation
Install 🤗 Optimum with the following command for ONNX Runtime support:
```
pip install optimum["onnxruntime"]
```
## Stable Diffusion
### Inference
To load an ONNX model and run inference with ONNX Runtime, you need to replace [`StableDiffusionPipeline`] with `ORTStableDiffusionPipeline`. In case you want to load a PyTorch model and convert it to the ONNX format on-the-fly, you can set `export=True`.
```python
from optimum.onnxruntime import ORTStableDiffusionPipeline
model_id = "runwayml/stable-diffusion-v1-5"
pipeline = ORTStableDiffusionPipeline.from_pretrained(model_id, export=True)
prompt = "sailing ship in storm by Leonardo da Vinci"
image = pipeline(prompt).images[0]
pipeline.save_pretrained("./onnx-stable-diffusion-v1-5")
```
If you want to export the pipeline in the ONNX format offline and later use it for inference,
you can use the [`optimum-cli export`](https://huggingface.co/docs/optimum/main/en/exporters/onnx/usage_guides/export_a_model#exporting-a-model-to-onnx-using-the-cli) command:
```bash
optimum-cli export onnx --model runwayml/stable-diffusion-v1-5 sd_v15_onnx/
```
Then perform inference:
```python
from optimum.onnxruntime import ORTStableDiffusionPipeline
model_id = "sd_v15_onnx"
pipeline = ORTStableDiffusionPipeline.from_pretrained(model_id)
prompt = "sailing ship in storm by Leonardo da Vinci"
image = pipeline(prompt).images[0]
```
Notice that we didn't have to specify `export=True` above.
You can find more examples in [optimum documentation](https://huggingface.co/docs/optimum/).
### Supported tasks
| Task | Loading Class |
|--------------------------------------|--------------------------------------|
| `text-to-image` | `ORTStableDiffusionPipeline` |
| `image-to-image` | `ORTStableDiffusionImg2ImgPipeline` |
| `inpaint` | `ORTStableDiffusionInpaintPipeline` |
## Stable Diffusion XL
### Export
To export your model to ONNX, you can use the [Optimum CLI](https://huggingface.co/docs/optimum/main/en/exporters/onnx/usage_guides/export_a_model#exporting-a-model-to-onnx-using-the-cli) as follows :
```bash
optimum-cli export onnx --model stabilityai/stable-diffusion-xl-base-1.0 --task stable-diffusion-xl sd_xl_onnx/
```
### Inference
Here is an example of how you can load a SDXL ONNX model from [stabilityai/stable-diffusion-xl-base-1.0](https://huggingface.co/stabilityai/stable-diffusion-xl-base-1.0) and run inference with ONNX Runtime :
```python
from optimum.onnxruntime import ORTStableDiffusionXLPipeline
model_id = "stabilityai/stable-diffusion-xl-base-1.0"
pipeline = ORTStableDiffusionXLPipeline.from_pretrained(model_id)
prompt = "sailing ship in storm by Leonardo da Vinci"
image = pipeline(prompt).images[0]
```
### Supported tasks
| Task | Loading Class |
|--------------------------------------|--------------------------------------|
| `text-to-image` | `ORTStableDiffusionXLPipeline` |
| `image-to-image` | `ORTStableDiffusionXLImg2ImgPipeline`|
## Known Issues
- Generating multiple prompts in a batch seems to take too much memory. While we look into it, you may need to iterate instead of batching.