REST API (Representational State Transfer API) is the architectural style of interaction between the components of the distributed web application. In a general sense, the components in REST interact on the Internet as clients and servers.
For web services built in compliance with REST (i.e. not violating the limits imposed by it), the term RESTful is used. At the same time, no official standard exists for the RESTful web API because it is an architectural style and not a protocol. At the same time, most RESTful implementations use such standards as HTTP, URL, JSON and XML.