Building Real-Time Applications with WebSockets

Modern applications often need real-time communication with features like chat apps, live dashboards, or instant notifications that deliver updates the moment they occur. However, the traditional HTTP model follows a request-response pattern, where the server only responds when the client requests data. This approach works well for many tasks, but it isn’t ideal for real-time scenarios because the client must keep asking the server for updates, a process known as polling. Polling can be inefficient, slow, and resource-heavy, especially when updates need to happen frequently or immediately.

WebSockets solve this problem by providing a persistent, full-duplex connection between the client and server. Once established, both sides can send data at any time without the overhead of reconnecting.

Setting up a WebSocket server

To demonstrate WebSockets, we’ll use the ws library, a lightweight and widely used WebSocket library for Node.js.

We’ll create a server that:

• Accepts connections from WebSocket clients.

• Listens for messages from clients.

• Broadcasts messages to all connected clients.

The file websocket-server.js contains the implementation: