Format APIs

• HAL - Simple format that gives a consistent and easy way to hyperlink between resources in your API (see: HATEOAS).
• Hydra - Vocabulary for Hypermedia-Driven Web APIs (W3C).
• JSend - Simple specification that lays down some rules for how JSON responses from web servers should be formatted.
• JSON API - Standard for building APIs in JSON.
• JSON-LD - Standard for describing Linked Data and hypermedia relations in JSON (W3C).
• OData - Open protocol to allow the creation and consumption of queryable and interoperable RESTful APIs. Quite complex.
• RAML - Simple and succinct way to describe RESTful API.
• Schema.org - Collection of schemas describing common data models.