1xx Informational
These status codes indicate that the server has received the request and is continuing the process. They are provisional responses, meaning the client should wait for a final response.
100
ContinueThe server has received the request headers and the client should proceed to send the request body.
101
Switching ProtocolsThe server agrees to switch protocols as requested by the client (e.g., WebSocket upgrade).
102
ProcessingThe server is still working on the request, but has not completed it yet. Used to prevent timeouts.
103
Early HintsThe server is sending some response headers before the final HTTP message, allowing the client to preload resources.