WebSocket is a network protocol based on TCP enabling a permanent, bidirectional connection between client and server. Unlike classic HTTP, where every request establishes a new, unidirectional connection, a WebSocket connection stays open – both sides can send messages at any time, without the overhead of repeated HTTP headers. The result: lower latency and more efficient real-time communication.
The WebSocket handshake
A WebSocket connection begins as a normal HTTP request and then switches protocol:
- The client’s request: the client sends an HTTP request with the upgrade header field
Upgrade: websocket. - The server’s response: the server answers with HTTP status code 101 (Switching Protocols) and an encryption key for the connection.
- The connection is established: from this point on, both sides can send and receive messages in any order.
The connection is severed via a close message, triggered on active closing, timeout or network error and generally answered by the other side with a confirmation.
WebSocket itself brings no built-in encryption – for any production application, therefore, only the encrypted wss:// scheme (WebSocket Secure, the counterpart to HTTPS) should be used instead of the unencrypted ws://.
WebSocket vs. server-sent events vs. polling
Not every real-time requirement needs WebSocket’s full bidirectionality:
| WebSocket | Server-sent events (SSE) | HTTP polling | |
|---|---|---|---|
| Direction | Bidirectional | Server → client only | Client asks repeatedly |
| Protocol switch needed | Yes | No, normal HTTP | No, normal HTTP |
| Setup effort | Higher | Low | Low, but inefficient |
| Typical use | Chat, collaboration, gaming | Live updates, feeds | Simple, rare updates |
Typical use cases
WebSocket is used above all where continuous, bidirectional real-time communication is demanded: chat applications, live collaboration tools, online games, trading platforms and real-time dashboards with user interaction. When developing such applications, we deliberately pick the fitting protocol by actual need – as part of our custom software development.
The 2026 trend: server-sent events and WebTransport
For many use cases needing only server-to-client updates, the pragmatic trend has shifted towards server-sent events (SSE): SSE runs over normal HTTP without a protocol switch and is simpler to implement, deploy and debug than WebSocket. For genuine bidirectional communication, though, WebSocket remains the established choice. Alongside it, WebTransport reached an important milestone in 2026: with Safari support, the HTTP/3- and QUIC-based protocol now runs in all major browsers and avoids WebSocket’s structural weaknesses like head-of-line blocking – making a closer look worthwhile for new projects with particularly high real-time ambitions.
Conclusion
WebSocket remains the standard for applications needing genuine bidirectional real-time communication, even as lighter alternatives like server-sent events increasingly win over the simpler, one-directional use cases. Which protocol is the right choice for your project is something we’re happy to work out as part of our custom software development or in a free first conversation.
Häufige Fragen
When should I use WebSocket instead of normal HTTP?
What's the difference between WebSocket and server-sent events (SSE)?
Is WebSocket secure?
wss:// (WebSocket Secure), the counterpart to HTTPS, encrypts the connection via TLS. For any production application, only wss:// should be used instead of the unencrypted ws://.