REST, or Representational State Transfer, is an architectural style for designing networked applications. It’s not a protocol like HTTP or a technology stack, but rather a set of principles and constraints that guide the design of web services and APIs (Application Programming Interfaces). RESTful services are built around the following key principles:
- Stateless: Each request from a client to a server must contain all the information needed to understand and fulfill that request. In other words, the server should not store any client-specific information between requests. This makes RESTful services highly scalable and easy to cache.
- Client-Server: REST separates the concerns of the client (user interface) from the server (data storage and processing). This separation of concerns allows for greater flexibility and scalability because each can evolve independently.
- Uniform Interface: RESTful services have a consistent and uniform interface. They use standard HTTP methods like GET (retrieve data), POST (create data), PUT (update data), DELETE (remove data), and others. Additionally, they make use of standard HTTP status codes for indicating the result of a request.
- Resource-Based: In REST, resources are entities that can be identified by a unique URI (Uniform Resource Identifier). Resources can represent objects like users, products, or any other relevant entity. Clients interact with these resources using the HTTP methods.
- Representation: Resources can have multiple representations, such as JSON, XML, HTML, or others. Clients can specify their preferred representation using HTTP headers like “Accept” and “Content-Type.”
- Stateless Communication: Each request-response interaction is stateless. The server does not rely on any previous requests to understand the current one. Clients include all necessary information, such as authentication tokens, with each request.
- Layered System: REST architecture can include multiple layers, such as proxies, caches, and load balancers, which can enhance security, scalability, and performance. Each layer is transparent to the client.
RESTful services are widely used for building web APIs that allow different systems to communicate over the internet. They are known for their simplicity, scalability, and compatibility with HTTP, the foundation of the World Wide Web. Developers can create RESTful APIs using various programming languages and frameworks.
One of the key benefits of REST is its wide adoption and the ease with which clients can consume and interact with RESTful APIs. Many web and mobile applications rely on RESTful services to retrieve and manipulate data from servers.