Discussing RESTful services

REST stands for representational state transfer. It is an architectural style that defines a set of guidelines for building web services.

What is an architectural style? It's nothing but a concept with predefined principles. We will talk about these principles in a moment. When you follow REST, you are actually implementing the principles that are the building blocks of REST in your application.

However, the implementation of REST will definitely differ from developer to developer. There is no fixed implementation style. Don't get confused with architectural patterns, which are not concepts but the actual implementations. MVC is an architectural pattern as it has a fixed structure that defines how the components interact with each other where they can't be differently implemented. 

The following is a very simple diagram of a REST-based service:

To simplify things, consider the preceding diagram, which shows you a service that has certain methods, such as GET, POST, PUT, and DELETE. That is what this style is all about. When you design your service, which will have all these methods—with the intended operations inside them—we can consider it as a REST-based service, otherwise known as a RESTful service. More importantly, the service can be called from an application built in any platform and language as the service has a standard architecture.

As discussed, a RESTful service is a service that supports REST. Let's talk about the characteristics of REST so that we can understand what is expected from a service that is RESTful.