REST stands for Representational State Transfer, and it is a style of service rather than an exact specification. REST services consist of a number of uniquely identifiable “resources,” and there are only four operations one can perform with a resource: read it, modify it, delete it, or create a new one.
When REST services are exposed over HTTP (as is typically the case), URIs are used to refer to server-side resources, and operations on those resources are represented as the HTTP verbs GET, POST, DELETE, and PUT.
A simple example is a book database. A URI to a book could be:
isbn_id is the unique identifier ...