Representational State Transfer

Representational state transfer (REST) is a style of software architecture for building distributed applications and services. REST is an application architecture based on clients and servers. A client initiates a request to the server and the server processes the request and returns the appropriate resources. Resources are the data and information that are returned to the client. At any time, a client can either be transitioning between application states or "at rest". A client in a rest state is able to interact with users, but creates no load and consumes no per client storage on the servers or network. The client begins sending requests when it is ready to transition to a new state. While one or more requests are outstanding, the client is considered to be transitioning states. The representation of each application state contains links (URLs) that may be used the next time the client chooses to initiate a new state transition. Each URL is a representation of some object. An application gets the contents of that object using a request. An application that conforms to REST is considered RESTful.&;

Rest-style services are becoming very common on the web today and are surpassing traditional WSDL and SOAP. While the concept of REST isn't a standard, it does use standards like HTTP, URL, XML/HTML/GIF/JPG (resource representations), and text/xml, text/html, image/gif, image/jpg (MIME types). There are many examples of RESTful services that have been exposed across the web.