💌 Envelope: a JAX-native environment interface

# Create environments from JAX-native suites you have installed, ...
env = envelope.create("gymnax::CartPole-v1")

# ... interact with the environments using a simple interface, ...
state, info = env.init(key)
states, infos = jax.lax.scan(env.step, state, actions)
plt.plot(infos.reward.cumsum())

# ... and enjoy a powerful ecosystem of wrappers.
env = envelope.wrappers.AutoResetWrapper(env)
env = envelope.wrappers.VmapWrapper(env)
env = envelope.wrappers.ObservationNormalizationWrapper(env)

🌍 Simple, expressive interaction!

• Environments are pytrees. Squish them through JAX transformations and trace their parameters.
• Idiomatic jax-y interface of init(key: Key) -> State, Info and step(state: State, action: PyTree) -> State, Info. You can directly jax.scan over a step(...)!
• Spaces are super simple. No Tuple, Dict nonsense! There are two spaces: Continuous and Discrete, which you can compose into a PyTreeSpace.
• Explicit episode truncation supports correctly handling bootstrapping for value-function targets.
• No auto-reset by default. Resetting every step can be expensive!

💪 Powerful, composable wrappers!

• Carry state across episodes to track running statistics, for example to normalize observations.
• Composable wrappers can be stacked in any order. For example, ObservationNormalizationWrapper before vs. after VmapWrapper gives per-env vs. global normalization.

🔌 Adapters for existing suites

📦	# 🤖	# 🌍
brax	🕺	12
craftax	🕺	4
gymnax	🕺	24
jumanji	🕺 / 👯	25 / 1
kinetix	🕺	74
mujoco_playground	🕺	54
navix	🕺	41
Total	🕺 / 👯	234 / 1

envelope.create("📦::🌍")

let's you create environments from any of the above!

📝 Testing

• Default (no optional adapters deps required): uv run pytest -m "not adapters"
• Adapters suite (requires full adapters dependency group):
  • uv sync --group adapters
  • uv run pytest -m adapters
  • If any adapter dependency is missing/broken, the run will fail fast with an error telling you what to install.

🏗️ Installation

pip install jax-envelope

💞 Related projects

• stoa is a very similar project that provides adapters and wrappers for the jumanji-like interface.
• Check out all the great suites we have adapters for! gymnax, brax, jumanji, kinetix, craftax, navix, mujoco_playground.
• We will be adding support for jaxmarl and pgx in the future, as soon as we figured out the best ever MARL interface for JAX!