RESTAPIs

REST APIs are an architectural style for designing networked applications. They expose resources via unique URIs and operate on them using standard HTTP methods such as GET, POST, PUT, PATCH, and DELETE. Clients exchange representations of resources, typically in JSON or XML. REST emphasizes statelessness, client–server separation, cacheability, and a layered system, all connected through a uniform interface.

Uniform interface constraints include resource identification via URIs, manipulation through representations, self-descriptive messages, and hypermedia as the engine of application state (HATEOAS). In practice, HATEOAS is optional, but it can guide clients with hyperlinks for subsequent actions. REST also relies on standard HTTP status codes to indicate outcomes.

Design considerations cover resource modeling, URI design, versioning, and operations for listing, creating, updating, and deleting resources. Common patterns include pagination, filtering, and sorting. Resources should use plural nouns, and response bodies should leverage consistent representations and content negotiation.

Security and scalability practices include TLS, authentication and authorization (OAuth 2.0, API keys, JWTs), rate limiting, input validation, and comprehensive logging. CORS configuration is important for web clients, and caching policies should be explicit to improve performance.

REST APIs are widely used for web services because of simplicity and compatibility with HTTP tooling. They may incur over-fetching or under-fetching and are not always ideal for real-time or streaming needs. Alternatives such as GraphQL or gRPC address some use cases, but REST remains a common baseline for interoperability.