What makes a RESTful service?

There are four qualities of a RESTful interface:

Identify resources (URI in HTTP) - use the same URI regardless of any operation. Change with representations (Verbs in HTTP) - use verbs, headers, and body. Self-descriptive error message (status response in HTTP) - Use status codes, don’t reinvent the wheel. HATEOAS (HTML interface for HTTP) - your web service should be fully accessible in a browser.