1xx Status Codes
1xx informational response
Section titled “1xx informational response”100 Continue
Section titled “100 Continue”The server has received the request headers, and the client can now send the body of the request.
101 Switching Protocols
Section titled “101 Switching Protocols”The server has agreed to switch protocols as requested by the client.
102 Processing (WebDAV)
Section titled “102 Processing (WebDAV)”The server is still processing the request, but there is no response yet, preventing the client from timing out.
103 Early Hints
Section titled “103 Early Hints”The server sends some response headers before the final response.
Caching warning codes (obsoleted)
Section titled “Caching warning codes (obsoleted)”110 Response is Stale
Section titled “110 Response is Stale”The cached response is outdated and no longer fresh.
111 Revalidation Failed
Section titled “111 Revalidation Failed”The cache couldn’t check if the response is still valid because it couldn’t reach the original server.
112 Disconnected Operation
Section titled “112 Disconnected Operation”The cache is purposely disconnected from the network.
113 Heuristic Expiration
Section titled “113 Heuristic Expiration”The cache set an expiration time over 24 hours, and the response is now too old.
199 Miscellaneous Warning
Section titled “199 Miscellaneous Warning”A general warning that may be logged or shown to the user.