REST

Definition

REST is an architectural style for developing web services. It defines 6 design principles, used for APIs.

Principles

1. Uniform interface: All API requests for the same resource should look the same, no matter where the request comes from.

2. Client-server decoupling: In REST API design, client and server applications must be completely independent of each other.

3. Statelessness: REST APIs are stateless, meaning that each request needs to include all the information necessary for processing it.

4. Cacheability: When possible, resources should be cacheable on the client or server side.

5. Layered system architecture: In REST APIs, the calls and responses go through different layers. REST APIs need to be designed so that neither the client nor the server can tell whether it communicates with the end application or an intermediary.

6. Code on demand (optional): REST APIs usually send static resources, but in certain cases, responses can also contain executable code (such as Java applets).

How it works

REST APIs communicate via HTTP requests to perform standard database functions like creating, reading, updating and deleting records (CRUD) within a resource.

The response can be delivered to a client in any format including JSON, HTML, XLT, Python, PHP, or plain text. JSON is popular because it’s readable by both humans and machines—and it is programming language-agnostic.

Request headers and parameters are also important in REST API calls because they include important identifier information such as metadata, authorizations, uniform resource identifiers (URIs), caching, cookies and more.