101101 Switching Protocols
The server is switching protocols as requested by the client via an Upgrade header.
410The resource is no longer available and has been permanently removed. Unlike 404, this indicates intentional removal.
The resource existed previously but has been permanently deleted. The server is explicitly telling clients to remove any references to it. This is stronger than 404 as it confirms the resource will not return.
Remove all references to this resource. Update bookmarks and links. If you expected the resource to exist, check if it was intentionally deprecated or moved to a different endpoint.
101The server is switching protocols as requested by the client via an Upgrade header.
403The server understood the request but refuses to authorize it. Unlike 401, re-authenticating will not help.
401The request requires user authentication. The client must provide valid credentials to access the resource.
500The server encountered an unexpected condition that prevented it from fulfilling the request.
418The server refuses the request because it is, permanently, a teapot. An April Fools' joke from RFC 2324.
203The response has been modified by a transforming proxy and differs from what the origin server sent.