# Defining custom data types in Jax using hijax

The article introduces "hijax," a technique for defining new Jax types that integrate with Jax's automatic differentiation and compilation. This allows developers to extend Jax's functionality for custom data structures, improving flexibility in machine learning workflows.

**Importance:** 3/5

## Sources

### Technology
- [Hacker News](https://docs.jax.dev/en/latest/hijax_types.html) — Sun, 12 Jul 2026 19:54:30 +0000