What is a REST API?

Introduction

A REST API is a way for different applications to communicate with each other over the internet.

For example:

• A mobile app talks to a server
• A website fetches user data
• A payment app sends transaction details
• A frontend React app communicates with a Django backend

All of this communication usually happens using a REST API.

Simple Definition

REST API = A bridge between two systems

REST stands for:

Representational State Transfer

API stands for:

Application Programming Interface

In simple words:

A REST API allows applications to send and receive data using HTTP requests.

Real-World Example

Imagine you are using a food delivery app.

When you:

• Open the app
• Search for pizza
• Place an order

The app sends requests to the server using a REST API.

The server then:

• Processes your request
• Fetches data from the database
• Sends the response back

REST API Architecture

How REST API Works

A REST API works using HTTP methods.

Common HTTP Methods

Example of REST API

Fetch User Data

GET /api/users/1

GET /api/users/1

Response

{
  "id": 1,
  "name": "Babu",
  "email": "babu@example.com"
}

{
  "id": 1,
  "name": "Babu",
  "email": "babu@example.com"
}

Here:

• Client sends request
• Server processes it
• Server returns JSON data

Main Components of a REST API

1. Client

The application that sends requests.

Examples:

• Mobile app
• Website
• React frontend

2. Server

The system that processes requests and returns responses.

Examples:

• Django
• FastAPI
• Flask
• Node.js

3. Database

Stores application data.

Examples:

• PostgreSQL
• MySQL
• MongoDB

Why REST APIs Are Popular

1. Easy to Understand

REST APIs use simple HTTP methods.

2. Fast Communication

Applications can exchange data quickly.

3. Platform Independent

Works with:

• Web apps
• Mobile apps
• Desktop apps

4. Uses JSON Format

JSON is lightweight and easy to read.

Example:

{
  "product": "Laptop",
  "price": 50000
}

{
  "product": "Laptop",
  "price": 50000
}

REST API Example in Real Life

Common REST API Response Codes

Important Features of REST API

1. Stateless

Each request is independent.

The server does not remember previous requests.

2. Client-Server Architecture

Frontend and backend work separately.

3. Cacheable

Responses can be stored temporarily for better performance.

4. Uniform Interface

Uses standard URLs and HTTP methods.

REST API URL Example

https://example.com/api/users

https://example.com/api/users

Breakdown: