REST API Design Made Simple with Express.js
In modern web development, applications need to communicate with each other. For example:
A frontend app needs data from a backend server
A mobile app needs user information from an API
A website needs to save or fetch data from a database
This communication happens through something called an API (Application Programming Interface).
A REST API is one of the most popular ways to build APIs.
What is REST API?
REST stands for Representational State Transfer.
REST API is a way for client and server to communicate using HTTP requests.
In REST:
Client sends a request (browser/app)
Server processes that request
Server sends back a response
REST APIs are widely used because they are simple, scalable, and easy to understand.
API as Communication System
Think of an API like a waiter in a restaurant:
You (client) place an order
Waiter (API) takes the order to kitchen (server)
Kitchen prepares food (data processing)
Waiter brings food back (response)
API is the bridge between client and server.
What are Resources in REST?
In REST, everything is treated as a resource.
A resource is any data object like:
Users
Products
Orders
Posts
Each resource has a unique URL.
Example:
/users→ all users/users/1→ user with ID 1
HTTP Methods in REST API
REST uses HTTP methods to perform actions on resources.
1. GET (Read Data)
Used to fetch data from server.
GET /users
Example: Get all users or a single user.
2. POST (Create Data)
Used to create new data.
POST /users
Example: Add a new user to database.
3. PUT or PATCH (Update Data)
Used to update existing data.
PUT /users/1
Example: Update user with ID 1.
4. DELETE (Remove Data)
Used to delete data.
DELETE /users/1
Example: Delete user with ID 1.
Status Codes in REST API
Status codes tell the result of a request.
Common Status Codes:
200 OK → Request successful
201 Created → New data created
400 Bad Request → Invalid input
401 Unauthorized → Login required
404 Not Found → Resource not found
500 Server Error → Something went wrong on server
Simple Example with Users Resource
Get Users
GET /users
Response:
[
{ "id": 1, "name": "Rahul" },
{ "id": 2, "name": "Amit" }
]
Create User
POST /users
Request:
{
"name": "John"
}
Response:
{
"message": "User created successfully"
}
REST Route Design Principles
Good REST APIs follow clean naming rules:
Good Practice:
/users/users/1/products/orders
Bad Practice:
/getUsers/createUser/deleteUser?id=1
REST uses nouns, not verbs
REST Request-Response Flow
Client Request
↓
HTTP Method (GET/POST/PUT/DELETE)
↓
Server processes that request
↓
Database operation (optional)
↓
Server sends response
↓
Client receives data
Conclusion
REST API is a simple and powerful way for communication between client and server. It uses HTTP methods to perform actions on resources and follows a clean structure for building scalable applications.
REST APIs make web development structured, predictable, and easy to scale
