REST

REST (Representational State Transfer) is an architectural style for designing networked interfaces in which applications communicate over the HTTP protocol and data is treated as resources that each have a unique address (URL). An interface built to REST principles is called a RESTful API, and it is today the most common way to exchange data between front ends, mobile apps and external services.

How REST works

In REST, every resource — a user, an order, a product — has its own address, and operations on it are expressed with standard HTTP methods:

• GET — retrieve a resource (for example a list of orders),
• POST — create a new resource,
• PUT / PATCH — update an existing resource,
• DELETE — remove a resource.

Responses are most often returned as JSON, and the outcome of each operation is signalled by HTTP status codes (200, 201, 404, 500). A defining trait of REST is statelessness: the server does not remember previous requests, so every request must be self-contained. Good practices also include a consistent URL structure, API versioning and disciplined use of status codes.

REST in practice

REST underpins most modern APIs: a mobile app fetches data from a server, a store integrates with a payment system, and an admin panel talks to the backend all through REST calls. Statelessness makes horizontal scaling easy — you can add servers without sharing sessions, which pairs well with running an application on VPS servers behind a load balancer. Alternatives to REST include the older SOAP and the newer GraphQL, but for most web use cases REST remains the default choice thanks to its simplicity and ubiquity.