How to Build a Chat Application with Node.js and
6 mins read

By: vishwesh

How to Build a Chat Application with Node.js and

In this tutorial, we will guide you through the process of building a chat application using Node.js and This tutorial is aimed at beginners who are interested in learning how to create real-time communication applications. We will cover all the necessary steps from setting up the environment to implementing the chat functionality. So let's get started!

Table of Contents


Before we begin, make sure you have the following prerequisites installed on your system:

  • Node.js - Node.js is a JavaScript runtime environment that allows you to run JavaScript on the server side.
  • npm - npm is the package manager for Node.js. It is used to install and manage dependencies for your project.

Setting up the Project

To start with, create a new directory for your project and navigate to it using the command line or terminal. Then, initialize a new Node.js project by running the following command:

$ npm init -y

This will create a new package.json file in your project directory, which will track the dependencies and configuration of your project.

Next, we need to install the necessary dependencies for our chat application. Run the following command to install express and

$ npm install express

The express package will be used to create the web server, and will handle real-time communication between the server and the clients.

Creating the Server

Now that we have set up our project, let's create the server file. Create a new file named server.js in your project directory and open it in a text editor.

First, we need to import the required modules. Add the following lines to the server.js file:

const express = require('express');
const app = express();
const http = require('http').Server(app);
const io = require('')(http);

Here, we import the necessary modules and create an Express application (app). We also create an HTTP server using the http module and pass it to the module to enable real-time communication.

Setting Up

To set up, we need to define the events that will handle the communication between the server and the clients. Add the following code to your server.js file:

io.on('connection', (socket) => {
  console.log('A user connected');

  socket.on('disconnect', () => {
    console.log('A user disconnected');

  socket.on('chat message', (message) => {
    console.log('Received message:', message);
    io.emit('chat message', message);

In this code snippet, we listen for the connection event, which is emitted when a new client connects to the server. Inside the connection event listener, we handle the disconnect event to log when a user disconnects.

We also handle the chat message event, which is emitted when a user sends a chat message. We log the received message and emit the chat message event to all connected clients using io.emit().

Now that we have set up the server and defined the communication events, let's move on to implementing the chat functionality.

Implementing the Chat Functionality

To implement the chat functionality, we need to handle the events on the client-side as well. Create a new file named index.html in your project directory and add the following HTML code:

<!DOCTYPE html>
  <title>Chat Application</title>
  <ul id="messages"></ul>
  <form id="chat-form">
    <input id="message-input" autocomplete="off" />
    <button type="submit">Send</button>

  <script src="/"></script>
    const socket = io();

    const messageForm = document.getElementById('chat-form');
    const messageInput = document.getElementById('message-input');
    const messagesList = document.getElementById('messages');

    messageForm.addEventListener('submit', (e) => {
      const message = messageInput.value.trim();
      if (message) {
        socket.emit('chat message', message);
        messageInput.value = '';

    socket.on('chat message', (message) => {
      const li = document.createElement('li');
      li.textContent = message;

In this HTML code, we have a form with an input field and a send button for users to enter and submit their chat messages. The received messages are displayed in an unordered list (ul) with the id messages.

We also import the client library by including the script tag <script src="/"></script>. This allows the client-side JavaScript code to establish a connection with the server.

The JavaScript code at the bottom sets up the event listeners for the form submission and the chat message event. When a user submits a message, the event listener sends the message to the server using socket.emit('chat message', message). The event listener for the chat message event appends the received message to the messages list.

Creating the User Interface

With the server and client-side functionality implemented, let's create a user interface to view and interact with the chat application.

Open the server.js file again and add the following lines of code after the previous code snippet:

app.get('/', (req, res) => {
  res.sendFile(__dirname + '/index.html');

Here, we define a route for the root URL ("/") and send the index.html file as the response.

Testing the Application

To test the chat application, start the server by running the following command in your project directory:

$ node server.js

You should see a message indicating that the server is running. Open your web browser and navigate to http://localhost:3000 (or the appropriate port if you have configured it differently).

You can open multiple browser tabs or windows and start sending messages. You will see that the messages are displayed in real-time across all connected clients.

Congratulations! You have successfully built a chat application using Node.js and


In this tutorial, we covered the step-by-step process of building a chat application with Node.js and We started by setting up the project, creating the server, and setting up for real-time communication.

Next, we implemented the chat functionality on both the server and the client-side. Users could send and receive messages in real-time. 

Finally, we created a simple user interface using HTML and JavaScript to interact with the chat application. Users could enter their messages and see them displayed in real-time.

Throughout the tutorial, we covered the fundamental concepts of building a chat application using Node.js and However, there are many additional features and improvements you can explore to enhance the functionality and user experience of your chat application. Here are a few ideas to consider:

User Authentication: Implement user authentication to secure the chat application and allow users to create accounts, log in, and have personalized chat experiences.

User Presence: Show the online/offline status of users in the chat room, indicating whether they are currently active or not.

Private Messaging: Enable private messaging between users by implementing direct messaging functionality.

Message Formatting: Enhance the chat messages by supporting rich text formatting, emojis, or file attachments.

Multiple Chat Rooms: Allow users to join different chat rooms or create their own chat rooms to facilitate group discussions on specific topics.

Message History: Implement a message history feature to retrieve previous chat messages when a user joins the chat room.

Remember to handle potential security concerns and optimize the performance of your application as it scales by implementing appropriate security measures and considering server load balancing.

As you continue to explore and expand your chat application, it's essential to refer to the official documentation of Node.js, Express, and for more in-depth understanding and to discover additional features and possibilities.

Happy coding, and enjoy building your chat application with Node.js and!

Recent posts

Don't miss the latest trends

    Popular Posts

    Popular Categories