WebSocket Communication in Node.js With Native ws Library

WebSockets enable real-time, two-way communication between clients and servers over a single TCP connection. They’re perfect for building chat apps, live notifications, collaborative tools, and more. In this guide, we’ll walk through implementing a basic WebSocket server and client using Node.js and the ws library.

Step 1: Install the ws Library

npm install ws

Step 2: Create a WebSocket Server

// server.js
const WebSocket = require('ws');
const server = new WebSocket.Server({ port: 8080 });

server.on('connection', socket => {
  console.log('Client connected');

  socket.on('message', message => {
    console.log(`Received: ${message}`);
    // Echo the message back
    socket.send(`Server says: ${message}`);
  });

  socket.on('close', () => {
    console.log('Client disconnected');
  });
});

This sets up a WebSocket server on port 8080. When a client connects, it can send and receive messages in real time.

Step 3: Create a WebSocket Client (Browser)

<script>
  const socket = new WebSocket('ws://localhost:8080');

  socket.addEventListener('open', () => {
    console.log('Connected to WebSocket server');
    socket.send('Hello from client!');
  });

  socket.addEventListener('message', event => {
    console.log('Message from server:', event.data);
  });

  socket.addEventListener('close', () => {
    console.log('Connection closed');
  });
</script>

Step 4: Broadcast Messages to All Clients

server.on('connection', socket => {
  socket.on('message', message => {
    // Broadcast to all connected clients
    server.clients.forEach(client => {
      if (client !== socket && client.readyState === WebSocket.OPEN) {
        client.send(`Broadcast: ${message}`);
      }
    });
  });
});

Security Note

For production use, always secure your WebSocket connection using WSS (WebSocket over HTTPS), and validate or sanitize all messages to avoid injection attacks.

Conclusion

The ws library offers a powerful and minimal API for real-time communication in Node.js. It’s lightweight, fast, and production-ready for many use cases, from live dashboards to collaborative tools and gaming backends.

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