Glossary

REST

REST (Representational State Transfer) is an architectural style for building APIs over HTTP. Resources are addressed via URLs, and actions on them use standard HTTP methods. REST is not a protocol or standard — it is a set of constraints that make APIs predictable and scalable.

Key principles

Stateless — each request contains all necessary information; the server stores no state between requests
Uniform interface — GET reads, POST creates, PUT/PATCH updates, DELETE removes
Resources — nouns in URLs (/users/42), not verbs (/getUser)
Cacheability — responses can be cached, reducing server load

Response codes

200 OK, 201 Created, 400 Bad Request, 401 Unauthorized, 404 Not Found, 422 Unprocessable Entity, 500 Internal Server Error — using them correctly makes an API self-documenting.