What Is a REST API? Explained Simply

What REST is

REST, which stands for Representational State Transfer, is an architectural style for designing networked applications, most commonly web APIs. An API that follows REST's principles is called RESTful. Rather than being a strict protocol, REST is a set of conventions for how a client and server should communicate over the web. It has become the dominant style for web APIs because it is simple, uses existing web standards, and is easy to understand and scale.

Everything is a resource

A core idea of REST is that everything is treated as a resource, a user, a photo, an order, and each resource has its own address in the form of a URL. For example, a URL might represent 'all users' or 'the user with a specific ID.' Clients interact with these resources through their URLs. This resource-oriented design maps neatly onto how the web already works, which is a big part of why REST feels natural for web services.

Standard HTTP methods

REST uses the standard HTTP methods your browser already relies on to act on resources. GET retrieves data, POST creates something new, PUT or PATCH updates an existing resource, and DELETE removes one. So to get a user you send a GET request to that user's URL; to create one you POST to the users URL. Reusing these well-defined methods gives REST APIs a predictable, consistent structure that developers can learn quickly.

Statelessness

Another key REST principle is statelessness: each request from a client contains all the information the server needs to handle it, and the server does not store client context between requests. Every request stands on its own. This makes REST APIs easier to scale, because any server can handle any request without needing to remember previous ones, and it simplifies the design by removing hidden session state from the interaction.

Data formats and responses

REST APIs typically exchange data in a structured format, most commonly JSON, which is lightweight and easy for both humans and machines to read. Responses also include HTTP status codes that signal the outcome, such as 200 for success, 404 for not found, or 500 for a server error. This combination of JSON data and standard status codes makes REST responses clear and easy to work with across many languages and platforms.

Why it matters

REST became the default style for web APIs because it leverages the web's own standards, URLs, HTTP methods, status codes, into a simple, consistent pattern. Understanding REST clarifies how the vast majority of web services are structured and how apps communicate with servers. Even as newer approaches like GraphQL emerge, REST remains foundational, and knowing it helps you read API documentation and understand how the connected software you use is built.

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See also: What is an API? Explained simply, What is JSON? Explained.

Sources

• REST - Wikipedia

Published date reflects the original event date (2025-01-14). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.