HAL

The Hypertext Application Language (HAL) is a simple, vendor-neutral media type for representing resources and their relationships in JSON or XML, designed to make RESTful APIs more discoverable and self-descriptive. In HAL, each resource’s state is represented by its attributes, its hyperlinks by a standardized “_links” section (allowing clients to navigate between related resources), and any embedded sub‐resources by an “_embedded” section. By providing a consistent convention for linking and embedding, HAL enables clients to follow HATEOAS principles—dynamically discovering available operations and transitions—without relying on out-of-band documentation.