Farama-Foundation/Gymnasium

Health v2 · maintenance only

Adoption not part of the score

12408 stars · 1434 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Gymnasium is a Python library providing a standard API for single-agent reinforcement learning environments, maintained by the Farama Foundation as the successor to OpenAI's Gym. It ships a diverse collection of reference environments (Classic Control, Box2D, Toy Text, MuJoCo, Atari) plus utilities like wrappers and vectorization.

Use cases

• train and benchmark RL algorithms on standard environments
• create custom reinforcement learning environments with a standard API
• debug RL algorithm implementations on simple toy text environments
• vectorize environments for faster parallel RL training
• wrap environments to modify actions, observations, or rewards
• migrate code from OpenAI Gym to a maintained fork

When to choose

• you need a well-maintained, standard RL environment API in Python
• you want ready-made reference environments like CartPole, Lunar Lander, or MuJoCo tasks
• you are developing or comparing single-agent RL algorithms
• you are starting a new RL project and need ecosystem compatibility

When to avoid

• you need multi-agent RL environments (use PettingZoo instead)
• you need OpenAI Gym specifically for legacy compatibility
• you need GPU-accelerated environments (consider Brax or Isaac Gym)
• your project depends on the old gym package and cannot migrate

Facets

library · maturity stable

machine-learning reinforcement-learning simulation sdk reinforcement-learning machine-learning artificial-intelligence python cross-platform reinforcement-learning gym environments api-standard mujoco atari farama-foundation game-development

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