HTTP Status Code Reference

Server cannot process the request due to a client error (malformed syntax, invalid framing).

Authentication is required and has failed or not been provided.

Reserved for future use; sometimes used by payment-gated APIs.

Server understood the request but refuses to authorize it.

Server cannot find the requested resource.

Request method is known but not supported by the target resource.

The resource cannot generate content matching the client's Accept header.

Client must authenticate itself with the proxy first.

Server timed out waiting for the request from the client.

Request conflicts with the current state of the resource.

Resource is permanently no longer available, with no forwarding address.

Server requires a Content-Length header but the request did not provide one.

One or more conditions in request headers (e.g., If-Match) evaluated to false.

Request body is larger than the server is willing or able to process.

Request URI is longer than the server is willing to interpret.

Server refuses the request because the payload format is unsupported.

Range specified in the Range header cannot be fulfilled.

Server cannot meet the requirements of the Expect request header.

Easter-egg status code from RFC 2324 (Hyper Text Coffee Pot Control Protocol).

Request was directed at a server unable to produce a response for the combination of scheme and authority.

Request is well-formed but semantically invalid.

Resource being accessed is locked (WebDAV).

Request failed because it depended on another request that failed.

Server is unwilling to risk processing a request that might be replayed.

Server refuses to perform the request using the current protocol but might if the client upgrades.

Origin server requires the request to be conditional.

Client has sent too many requests in a given amount of time (rate limiting).

Request headers are too large for the server to process.

Resource is unavailable due to a legal demand (e.g., government censorship).

Non-standard nginx code: the client closed the connection before the server could finish responding.