Restful(https://en.wikipedia.org/wiki/Representational_state_transfer) service is something very popular these years .before to make your service RESTful , it’s important to understand what it really is .
Stateless .there should not be any state stored in service. this is decouple the client request from any specified machine .
Identification of resources .decouple finding resource from providing resource . include how to find resource (URL, file format, HTTP Get), resource format ,etc.
Manipulation of resources through representations (Post, Delete, Update). decouple client logic operating on the resource from server .
Self-descriptive messages. message itself defines how to process this message .the way processing message doesn’t rely on client or server .
Hypermedia as the engine of application state (HATEOAS) .decouple client development from server development .
In short ,The whole point of Restful is about decouple ‘client world’ from ‘server world’.
In software ,abstraction is the blood and bones.same to RESTful. consider RESTful as an abstraction between client and service ,which stands for some rules of how client talk to server .which helps simplified the communication between client and server ,speeds up development(for client-server architecture system) as well.