1xx InformationalHTTP Status Code Reference

HTTP 101 Switching Protocols— What It Means, Causes & How to Fix It

The server is switching protocols as requested by the client via an Upgrade header. This is commonly used when upgrading an HTTP connection to WebSocket.

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Common Causes

  • WebSocket connection upgrade request
  • HTTP/2 upgrade negotiation
  • Protocol switch requested via Upgrade header

How to Fix

  1. 1No fix needed — this is expected during protocol upgrades
  2. 2Ensure both client and server support the target protocol
  3. 3Verify the Upgrade header specifies a valid protocol

Example

HTTP 101 Switching Protocols
GET /chat HTTP/1.1
Upgrade: websocket
Connection: Upgrade

→ Server responds 101 Switching Protocols

Related Informational Codes

100

Continue

102

Processing

103

Early Hints

Commonly Referenced Status Codes

The most frequently searched HTTP status codes

200OK201Created204No Content301Moved Permanently302Found400Bad Request401Unauthorized403Forbidden404Not Found422Unprocessable Content429Too Many Requests500Internal Server Error502Bad Gateway503Service Unavailable504Gateway Timeout

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