REST APIs have become a popular way of providing application features as a service in all types of web application. It's already become the standard for providing third-party access and could well be the future of web application development. Most popular online applications such as Facebook, Twitter, Google, LinkedIn, and Amazon provide features to application developers through a well defined REST API. Let's take a look at the Wikipedia definition to identify what REST is and how it works:
"Representational state transfer (REST) or RESTful Web services are one way of providing interoperability between computer systems on the Internet. REST-compliant Web services allow requesting systems to access and manipulate textual representations of Web resources using a uniform and predefined set of stateless operations."
Basically, REST API is a set of functions...