Keras

Keras 3 is a game changer: it is now multi-backend. You can write Keras code and run it on top of JAX, PyTorch, or TensorFlow.

When to Use

• Portability: Write once, run on any framework.
• Simplicity: model.fit() is still the cleanest API in the industry.
• XLA: Keras 3 enables XLA compilation on all backends by default.

Core Concepts

Backend Agnostic

The Model is just a blueprint. You choose the engine at runtime. os.environ["KERAS_BACKEND"] = "jax"

Functional API