REST - architectural approach for designing web services.
Independent of underlying protocol, but usually use HTTP as application protocol
It has:
- a URI (resource)
- uses a uniform interface for decoupling client and service
For example when built on top of http, the same uri can be used with standard http operations like get/post/put..

Stateless request model. Request should be independent from each other.
Also, each request should be an atomic operation.
(This enable web services to be scalable, because client and server do not need to retain information. Client request can go to any servers)