Request headers received; client should continue.

Server is switching protocols as requested.

Standard success response.

Resource created successfully.

Request accepted but not yet processed.

Success with no response body.

Range request served partially.

Resource permanently moved to a new URL.

Temporary redirect.

Cached version is still valid.

Repeat request to new URL, keep method.

Permanent, keep method and body.

Malformed or invalid request.

Authentication required or failed.

Authenticated but not allowed.

Resource does not exist.

HTTP method not supported for this resource.

Request conflicts with current state.

Resource permanently removed.

Refuses to brew coffee (RFC 2324 joke).

Validation failed on well-formed request.

Rate limit exceeded.

Generic server failure.

Server doesn't support the functionality.

Invalid response from upstream server.

Server temporarily overloaded or down.

Upstream server timed out.