Hydra is an effort to simplify the development of interoperable, hypermedia-driven Web APIs. The two fundamental building blocks of Hydra are JSON‑LD and the Hydra Core Vocabulary.

JSON‑LD is the serialization format used in the communication between the server and its clients. The Hydra Core Vocabulary represents the shared vocabulary between them. By specifying a number of concepts which are commonly used in Web APIs it can be used as the foundation to build Web services that share REST's benefits in terms of loose coupling, maintainability, evolvability, and scalability. Furthermore it enables the creation of generic API clients instead of requiring specialized clients for every single API.

Specifications

• Hydra Core Vocabulary
• JSON-LD 1.0

Playground

There exists a demo Web API featuring a simple issue tracker which allows you to try Hydra directly in your web browser:

Launch Hydra Console

Of course, the complete source code of the Hydra Issue Tracker Demo application is available for you to use as skeleton for your applications.

Source Code

The Hydra project currently consists of the following parts:

• HydraBundle: a bundle for Symfony2 to create Web APIs based on Hydra
• HydraConsole: a generic API console for Hydra-powered Web APIs
• HydraClient: a PHP client library to access Hydra-powered Web APIs
• JsonLD: a JSON-LD processor implemented in PHP

Publications/Presentations

• M. Lanthaler, “Building Next-Generation Web APIs with JSON-LD and Hydra,” presented at the Symfony Live Portland 2013 [slides] [video].
• M. Lanthaler and C. Gütl, “Hydra: A Vocabulary for Hypermedia-Driven Web APIs,” in Proceedings of the 6th Workshop on Linked Data on the Web (LDOW2013) at the 22nd International World Wide Web Conference (WWW2013), 2013 [slides].
• M. Lanthaler, “Creating 3rd Generation Web APIs with Hydra,” in Proceedings of the 22nd International World Wide Web Conference (WWW2013), 2013, pp. 35–37 [slides].
• M. Lanthaler and C. Gütl, “Model Your Application Domain, Not Your JSON Structures,” in Proceedings of the 4th International Workshop on RESTful Design (WS-REST 2013) at the 22nd International World Wide Web Conference (WWW2013), 2013, pp. 1415–1420 [slides].

Collaborating

Join the Hydra W3C Community Group. If you just wanna report a bug, either raise an issue on our issue tracker, submit a pull request, or send a mail to Hydra's public mailing list.