Django REST API – Introduction

Before building APIs with Django REST Framework, it is important to understand what a REST API is, how clients and servers communicate, and why APIs are so useful in modern web development.
In this introduction, we will look at the basic concepts behind REST APIs, HTTP methods, JSON responses, endpoints, and the role of Django REST Framework.


 

What is an API?
An API, or Application Programming Interface, is a way for two different applications to communicate with each other.

For example, a frontend application, mobile app, or another backend service can request data from your server through an API.

Client  →  API  →  Server
Client  ←  JSON Response  ←  Server

 

What is a REST API?
A REST API is an API that follows a set of architectural principles based on resources, HTTP methods, and stateless communication.

In simple terms, a REST API allows a client to interact with server-side data using URLs and standard HTTP methods.

GET     /api/projects/
POST    /api/projects/
GET     /api/projects/1/
PATCH   /api/projects/1/
DELETE  /api/projects/1/

 

Client and Server
In a web application, the client is the application that makes requests, and the server is the application that processes those requests and returns responses.

The client could be:

Web browser
React application
Mobile application
Another backend service

The server receives the request, processes it, interacts with the database if needed, and sends back a response.

Client sends a request
Server processes the request
Server returns a response

 

Resources and Endpoints
In REST APIs, data is usually represented as resources.

For example, in a project management API, we could have resources such as:

Projects
Tasks
Users
Comments

Each resource is accessed through an endpoint.

/api/projects/
/api/tasks/
/api/users/
/api/comments/

An endpoint is simply a URL that represents a specific resource or action in your API.

 

HTTP Methods
REST APIs use HTTP methods to define the type of action the client wants to perform.

GET     → Read data
POST    → Create data
PUT     → Replace data
PATCH   → Update part of the data
DELETE  → Delete data

For example, if we are working with tasks:

GET     /api/tasks/       → List all tasks
POST    /api/tasks/       → Create a new task
GET     /api/tasks/1/     → Retrieve task with ID 1
PATCH   /api/tasks/1/     → Update task with ID 1
DELETE  /api/tasks/1/     → Delete task with ID 1

 

JSON Responses
Most REST APIs return data in JSON format.

JSON is a lightweight data format that is easy for both humans and machines to read.

{
    "id": 1,
    "title": "Create Django REST API introduction",
    "completed": false
}

This makes it easy for frontend applications, mobile apps, and other services to consume data from your API.

 

Status Codes
When a server responds to a request, it also sends an HTTP status code.

Status codes help the client understand if the request was successful or if something went wrong.

200 OK                  → Request successful
201 Created             → Resource created successfully
400 Bad Request         → Invalid request data
401 Unauthorized        → Authentication required
403 Forbidden           → Permission denied
404 Not Found           → Resource not found
500 Internal Server Error → Server error

 

Why use Django REST Framework?
Django is excellent for building web applications, but when we want to build APIs, Django REST Framework gives us extra tools that make the process easier and more organized.

Django REST Framework helps with:

Serializing Django models into JSON
Creating API views
Handling authentication
Managing permissions
Filtering and pagination
Testing API endpoints
Generating API documentation

Instead of manually converting data into JSON and writing every API response from scratch, Django REST Framework provides reusable tools and patterns for building professional APIs.

 

Example API Flow
Let’s imagine a client wants to get a list of tasks.

Client sends:
GET /api/tasks/

Server returns:
[
    {
        "id": 1,
        "title": "Learn Django REST Framework",
        "completed": false
    },
    {
        "id": 2,
        "title": "Build a REST API",
        "completed": true
    }
]

The client does not need to know how the database works. It only needs to know which endpoint to call and how to use the response.

 

What we will build in this series
Throughout this series, we will build a simple project management REST API.

The API will include resources such as:

Projects
Tasks
Users

This will allow us to explore the most important concepts of Django REST Framework step by step.

In the next post, we will set up a Django project, install Django REST Framework, and prepare the base structure for our API.