What Is HTTP 101 Switching Protocols?

HTTP 101 Switching Protocols explained, and what it means when you see it in CI/CD and deployments.

HTTP 101 means the server is switching to the protocol the client requested.

What it means

A 101 is the handshake response when upgrading from HTTP to WebSocket (or HTTP/2 over cleartext). After it, the connection speaks the new protocol.

When you see it in CI/CD

In CI, a 101 shows up when testing WebSocket endpoints; assert the upgrade succeeded before exchanging messages.

Key takeaways

• 101 means switching protocols.
• Used for the WebSocket upgrade.
• Assert it in WebSocket tests.

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