---
title: "The ultimate guide to RL environments:\nbuilding and scaling them in the LLM era"
# Alternative titles (kept for reference — uncomment one and comment the active line above to swap):
# title: "The ultimate guide to RL environments in the LLM era — building, scoring, and scaling to thousands"
# title: "Building and scaling RL environments in the LLM era: the ultimate guide"
# title: "The ultimate playbook for RL environments in the LLM era: build, score, scale"
description: "The anatomy of RL environment frameworks for LLM training: how they're built, how rewards are wired, and how they scale to thousands of concurrent sessions."
authors:
  - name: "Adithya S Kolavi"
    url: "https://huggingface.co/AdithyaSK"
    affiliations: [1]
  - name: "Lewis Tunstall"
    url: "https://huggingface.co/lewtun"
    affiliations: [1]
  - name: "Leandro von Werra"
    url: "https://huggingface.co/lvwerra"
    affiliations: [1]
  - name: "Quentin Gallouédec"
    url: "https://huggingface.co/qgallouedec"
    affiliations: [1]
  - name: "Amine Dirhoussi"
    url: "https://huggingface.co/aminediroHF"
    affiliations: [1]
  - name: "Ben Burtenshaw"
    url: "https://huggingface.co/burtenshaw"
    affiliations: [1]
  - name: "Sergio Paniego"
    url: "https://huggingface.co/sergiopaniego"
    affiliations: [1]
affiliations:
  - name: "Hugging Face"
    url: "https://huggingface.co"
published: "May 5, 2026"
repo: "https://github.com/adithya-s-k/RL_Envs_101"
seoThumbImage: "https://raw.githubusercontent.com/adithya-s-k/RL_Envs_101/refs/heads/main/assets/blog_thumbnail.png"
template: "article"
tableOfContentsAutoCollapse: true
showPdf: true
---

import Introduction from "./chapters/introduction.mdx";
import WhyComparison from "./chapters/why-comparison.mdx";
import FrameworkInventory from "./chapters/framework-inventory.mdx";
import RlEnvironment from "./chapters/rl-environment.mdx";
import Dimensions from "./chapters/dimensions.mdx";
import ComparisonMatrix from "./chapters/comparison-matrix.mdx";
import FrameworkProfiles from "./chapters/framework-profiles.mdx";
import Observations from "./chapters/observations.mdx";

<Introduction />
<WhyComparison />
<FrameworkInventory />
<RlEnvironment />
<Dimensions />
<ComparisonMatrix />
<FrameworkProfiles />
<Observations />