// http 1xx · informational
HTTP 101 Switching Protocols
The server is switching protocols as the client asked (e.g. to WebSocket).
What HTTP 101 Switching Protocols means
101 Switching Protocols confirms the server is changing the protocol on this connection at the client's request — most commonly the upgrade from HTTP to WebSocket. After a 101, the connection is no longer speaking ordinary HTTP.
Which category is it?
101 is a 1xx code — Informational. 1xx responses are interim: the request was received and the process is continuing. The client should wait for the final response.