HTTP vs WebSocket

HTTP and WebSocket are complementary protocols. HTTP powers the majority of web traffic with its request-response model. WebSocket provides persistent, bidirectional communication for real-time features.

HTTP: The Foundation of the Web

HTTP is a stateless, request-response protocol. The client sends a request, the server returns a response, and the connection can be closed (or reused with keep-alive). This simplicity enables caching, load balancing, and the entire CDN infrastructure that powers the modern web.

HTTP/2 added multiplexing (multiple requests over one connection) and server push, narrowing the gap with WebSocket for some use cases.

WebSocket: Persistent Bidirectional Channel

WebSocket begins as an HTTP request with an Upgrade header. After the handshake, the TCP connection becomes a persistent, full-duplex channel. Both client and server can send messages at any time with minimal overhead (2-14 bytes per frame vs hundreds of bytes for HTTP headers).

The Right Tool for the Right Job

95% of web communication should use HTTP. It is simpler, more cacheable, and better supported by infrastructure. WebSocket should be reserved for features that genuinely need real-time bidirectional communication.

Common mistake in system design interviews: proposing WebSocket for everything. Most features — user profiles, search, forms — work perfectly with standard HTTP. See our system design interview guide for when to use each.

Explore our concepts library for protocol deep-dives and interview questions. Check pricing for full access.

The Bottom Line

Use HTTP for the 95% of your application that follows request-response patterns. Use WebSocket for the 5% that needs real-time, bidirectional communication.