Want to build a real-time chat app from scratch without relying on third-party services? With Node.js and WebSocket, you can create a lightweight chat server that delivers messages instantly between users.
In this post, you’ll learn how to build a simple chat server using Node.js and the ws WebSocket package — step by step.
🚀 Why Use WebSocket for Chat?
HTTP is request/response-based — not ideal for real-time messaging. WebSockets create a persistent, two-way connection between client and server, perfect for:
- Chat apps
- Live notifications
- Real-time dashboards
- Multiplayer games
🔧 Step 1: Initialize a Node.js Project
Create a new directory and initialize a Node.js app:
mkdir websocket-chat
cd websocket-chat
npm init -y
Install the ws package:
npm install ws
The ws package is a simple and efficient WebSocket library for Node.js. See more on the official npm page.
📁 Step 2: Create the Chat Server
Create a file named server.js:
const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 8080 });
console.log('WebSocket server started on ws://localhost:8080');
wss.on('connection', (ws) => {
console.log('New client connected.');
ws.on('message', (message) => {
console.log(`Received: ${message}`);
// Broadcast to all connected clients
wss.clients.forEach((client) => {
if (client !== ws && client.readyState === WebSocket.OPEN) {
client.send(message);
}
});
});
ws.on('close', () => {
console.log('Client disconnected.');
});
});
This server listens on port 8080, accepts connections, and broadcasts any received message to all other connected clients.
🧪 Step 3: Create a Simple HTML Client
Create a file named client.html:
<!DOCTYPE html>
<html>
<head><title>WebSocket Chat</title></head>
<body>
<h2>WebSocket Chat</h2>
<input id="msg" placeholder="Type a message..." />
<button onclick="sendMessage()">Send</button>
<ul id="messages"></ul>
<script>
const socket = new WebSocket('ws://localhost:8080');
const messages = document.getElementById('messages');
socket.onmessage = (event) => {
const li = document.createElement('li');
li.textContent = event.data;
messages.appendChild(li);
};
function sendMessage() {
const input = document.getElementById('msg');
socket.send(input.value);
input.value = '';
}
</script>
</body>
</html>
Open this file in two tabs or different browsers to simulate multiple users.
You can learn more about the WebSocket API in the official MDN documentation.
✅ Final Thoughts
You’ve now built a fully functional real-time chat server using Node.js and WebSocket — no external services, just code and sockets.
This is the foundation for more advanced features like:
- User authentication
- Message persistence (MongoDB, PostgreSQL, etc.)
- Private rooms or channels
- WebSocket with frontend frameworks (React, Vue, etc.)
WebSocket is a powerful tool for building real-time apps — and Node.js makes it fast and easy to get started.
