1xx Informational
HTTP 101 Switching Protocols
The server is switching protocols as requested by the client via the Upgrade header.
When is 101 used?
- Upgrading from HTTP to WebSocket
- Protocol negotiation for real-time communication
How to handle a 101 response
Clients rarely see these directly; HTTP libraries handle them before the final response arrives, and servers usually send them automatically.
Check the status code a URL returns from the command line:
curl -s -o /dev/null -w "%{http_code}\n" https://example.comFrequently Asked Questions
What does HTTP 101 mean?
101 Switching Protocols: The server is switching protocols as requested by the client via the Upgrade header.
Is 101 an error?
No. 101 is in the 1xx Informational class. Informational responses: the request was received and processing continues.