What are WebSockets?

WebSockets represent a fundamental shift in how web applications communicate with servers. While traditional HTTP follows a request-response pattern where clients must initiate all communications, WebSockets establish a persistent, full-duplex connection that allows both client and server to send messages at any time. This real-time, bidirectional communication enables a new class of interactive web applications.

The WebSocket protocol begins with an HTTP handshake where the client requests an "upgrade" to the WebSocket protocol. If the server agrees, the connection switches from HTTP to WebSocket, maintaining the established TCP connection. From that point, both parties can send messages with minimal overhead - no HTTP headers, no connection re-establishment, just raw data frames. This efficiency makes WebSockets ideal for applications requiring low latency or high message frequency.

Common use cases include chat applications where messages need instant delivery, collaborative editing tools where multiple users' changes must sync in real-time, live sports scores or stock tickers requiring constant updates, and online gaming where every millisecond counts. WebSockets also enable server-sent events without the overhead of long-polling or the complexity of server-sent events (SSE).

Implementation has become increasingly straightforward with libraries like Socket.IO providing fallbacks for older browsers and handling reconnection logic. However, WebSockets require different architectural considerations than traditional HTTP. Servers must maintain connection state, load balancing becomes more complex with persistent connections, and you need strategies for handling disconnections and reconnections. Despite these challenges, WebSockets have become essential for creating the responsive, real-time experiences users now expect from modern web applications.