HTTP status codes
Quick reference. Searchable.
Server acknowledges request headers, client should send body.
Server agrees to switch protocols (e.g., to WebSocket).
Standard success response.
Request fulfilled, new resource created (POST/PUT response).
Request accepted but processing not complete.
Success but no body to return (e.g., DELETE response).
Resource moved permanently. Update bookmarks.
Temporary redirect. Original URL still valid.
Cached resource still valid. Use local copy.
Like 302 but method must not change.
Like 301 but method must not change.
Request malformed. Client should fix and retry.
Authentication required or failed.
Authenticated but not authorized.
Resource does not exist.
HTTP method not supported on this endpoint.
Request conflicts with current state (e.g., duplicate).
Resource permanently removed. Stronger than 404.
April Fools RFC. Server refuses to brew coffee.
Syntactically valid but semantically wrong.
Rate limited. Back off.
Generic server error. Check server logs.
Server does not support the request method.
Upstream server returned invalid response.
Server overloaded or down for maintenance.
Upstream server did not respond in time.
Server out of storage to complete request.