REST

Representational State Transfer (REST) is an architectural style for distributed hypermedia systems like the world wide web. The term originated in a 2000 doctoral dissertation about the web written by Roy Fielding, one of the principal authors of the HTTP protocol specification, and has quickly passed into widespread use in the networking community.

REST's proponents argue that the web has enjoyed the scalability and growth that it has as a result of a few key design principles:

• A stateless client/server protocol: each HTTP message contains all the information necessary to understand the request. As a result, neither the client nor the server needs to remember any communication-state between messages. In practice, however, many HTTP-based applications use cookies and other devices to maintain session state (some of those practices, like URL-rewriting, are not RESTful).
• A set of well-defined operations that apply to all pieces of information (called resources): HTTP itself defines a small set of operations, the most important of which are GET, POST, PUT, and DELETE. People often compare these with the CRUD operations required for data persistence, though POST does not fit cleanly into the comparison.
• A universal syntax for resource-identification: in a RESTful system, every resource is uniquely addressable through the resource's URI.
• The use of hypermedia both for application information and application state-transitions: representations in a REST system are typically HTML or XML files that contain both information and links to other resources; as a result, it is often possible to navigate from one REST resource to many others, simply by following links, without requiring the use of registries or other additional infrastructure.