What Is a REST API?
REST APIs are the most common type of API used on the web today. They power websites, mobile applications, cloud platforms and countless software integrations.
If you’ve worked with APIs, there is a high chance you’ve already interacted with a REST API. Understanding how REST works is an essential skill for developers and anyone learning modern web development.
What Does REST Mean?
REST stands for Representational State Transfer. It is an architectural style for designing APIs that communicate over HTTP.
REST was introduced by Roy Fielding in his doctoral dissertation and has become the dominant approach for building web APIs.
How Does a REST API Work?
A REST API allows clients and servers to communicate using standard HTTP requests and responses.
The client sends a request to a specific endpoint and the server responds with data, usually in JSON format.
GET /users/123
The server may respond with:
{
"id": 123,
"name": "John"
}
REST API Endpoints
Endpoints are URLs that represent resources within a REST API.
For example:
/users /users/123 /products /orders
Each endpoint provides access to a specific resource or collection of resources.
Common HTTP Methods
GET
Retrieves data from the server.
POST
Creates a new resource.
PUT
Updates an existing resource.
DELETE
Removes a resource.
REST API Example
| Method | Endpoint | Purpose |
|---|---|---|
| GET | /users | Retrieve users |
| POST | /users | Create user |
| PUT | /users/123 | Update user |
| DELETE | /users/123 | Delete user |
Why REST APIs Are Popular
- Easy to understand.
- Uses standard HTTP protocols.
- Works with JSON.
- Highly scalable.
- Supported by virtually every programming language.
REST vs SOAP
| REST | SOAP |
|---|---|
| Lightweight | More complex |
| Usually JSON | Usually XML |
| Flexible | Strict standards |
| Popular for web APIs | Common in enterprise systems |
REST vs GraphQL
REST uses multiple endpoints for different resources, while GraphQL allows clients to request exactly the data they need through a single endpoint.
Both approaches are widely used depending on project requirements.
Common REST API Status Codes
- 200 OK
- 201 Created
- 400 Bad Request
- 401 Unauthorized
- 404 Not Found
- 500 Internal Server Error
Frequently Asked Questions
What is a REST API in simple terms?
A REST API is a way for applications to communicate using HTTP requests and standard web technologies.
Why are REST APIs so popular?
They are simple, scalable and work well with modern web applications.
Do REST APIs always use JSON?
No. JSON is the most common format, but REST APIs can return other formats as well.
Is REST the same as HTTP?
No. REST is an architectural style that commonly uses HTTP as its communication protocol.