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Express.js Tutorial

Last Updated : 15 Apr, 2024
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Express.js is a fast, flexible and minimalist web framework for Node.js. It’s effectively a tool that simplifies building web applications and APIs using JavaScript on the server side. Express is an open-source that is developed and maintained by the Node.js foundation.

Express.js offers a robust set of features that enhance your productivity and streamline your web application. It makes it easier to organize your application’s functionality with middleware and routing. It adds helpful utilities to Node HTTP objects and facilitates the rendering of dynamic HTTP objects.

Express.js Tutorial

Why learn Express?

Express is a user-friendly framework that simplifies the development process of Node applications. It uses JavaScript as a programming language and provides an efficient way to build web applications and APIs. With Express, you can easily handle routes, requests, and responses, which makes the process of creating robust and scalable applications much easier.

Moreover, it is a lightweight and flexible framework that is easy to learn and comes loaded with middleware options. Whether you are a beginner or an experienced developer, Express is a great choice for building your application.

Express Key Features

  1. Middleware and Routing: Express.js makes it easy to organize your application’s functionality using middleware and routing. Middleware functions allow you to handle tasks like authentication, logging, and error handling. Routing ensures that incoming requests are directed to the appropriate handlers.
  2. Minimalistic Design: Express.js follows a simple and minimalistic design philosophy. This simplicity allows you to quickly set up a server, define routes, and handle HTTP requests efficiently. It’s an excellent choice for building web applications without unnecessary complexity.
  3. Flexibility and Customization: Express.js doesn’t impose a strict application architecture. You can structure your code according to your preferences. Whether you’re building a RESTful API or a full-fledged web app, Express.js adapts to your needs.
  4. Scalability: Designed to be lightweight and scalable, Express.js handles a large number of requests asynchronously. Its event-driven architecture ensures responsiveness even under heavy loads.
  5. Active Community Support: With a thriving community, Express.js receives regular updates and improvements. You’ll find ample documentation, tutorials, and plugins to enhance your development experience.

Getting Started Express

1. Installation: Install Express using npm:

npm install express

2. Basic Example of an Express App:

const express = require('express');
const app = express();

// Define routes and middleware here
// ...

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
    console.log(`Server running on port ${PORT}`);


  1. Import the ‘express’ module to create a web application using Node.js.
  2. Initialize an Express app using const app = express();.
  3. Add routes (endpoints) and middleware functions to handle requests and perform tasks like authentication or logging.
  4. Specify a port (defaulting to 3000) for the server to listen on.

Express Basic:

Express Functions:

Express express():

Express Applications Function:

Express Requests Function:

Express Response Function:

Express Router Function:

Express Advanced Topics:

Advanced Concepts

  1. Template Engines: Use template engines like EJS or Pug for dynamic content rendering.
  2. Error Handling: Implement custom error handling middleware to gracefully handle exceptions.
  3. Authentication: Integrate authentication middleware (e.g., Passport.js) for secure user sessions.

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