Data lookups

HTTP status codes

What 404, 429, 502 and every other HTTP response code actually mean.

All lookups

46 entries.

CodeNameWhat it means
100 Continue Headers received; the client should send the request body.
101 Switching Protocols The server is changing protocol, typically upgrading to WebSockets.
103 Early Hints Preliminary headers so the browser can start preloading resources.
200 OK The request succeeded. The everyday success response.
201 Created The request succeeded and a new resource was created.
202 Accepted Accepted for processing, but not finished yet.
204 No Content Success, but there is deliberately nothing to return.
206 Partial Content Part of the file is being returned — used for range requests and video seeking.
301 Moved Permanently The resource has a new permanent URL. Search engines transfer ranking to it.
302 Found Temporary redirect. The original URL should keep being used.
303 See Other Fetch the result from another URL using GET — the redirect after a form POST.
304 Not Modified Your cached copy is still current, so nothing was sent.
307 Temporary Redirect Like 302, but the method (e.g. POST) must not be changed.
308 Permanent Redirect Like 301, but the method must not be changed.
400 Bad Request The server could not understand the request — usually malformed syntax or parameters.
401 Unauthorized Authentication is required or has failed. Really means "unauthenticated".
402 Payment Required Reserved for future use; some APIs use it for billing problems.
403 Forbidden The server understood but refuses. You are authenticated but not allowed.
404 Not Found Nothing exists at that URL. The most familiar error on the web.
405 Method Not Allowed The URL exists but not for that verb — e.g. POST to a GET-only page.
406 Not Acceptable The server cannot produce a response matching the Accept headers.
408 Request Timeout The client took too long to send the request.
409 Conflict The request clashes with the current state — e.g. a duplicate record.
410 Gone Deliberately removed and not coming back. Stronger than 404.
411 Length Required A Content-Length header is required and was missing.
413 Payload Too Large The request body exceeds the server limit — often a big file upload.
414 URI Too Long The URL is longer than the server will accept.
415 Unsupported Media Type The content type of the body is not supported.
418 I'm a teapot An April Fools joke from 1998 that is still in the standards.
422 Unprocessable Content Well-formed but semantically wrong — the usual API validation failure.
423 Locked The resource is locked and cannot be changed right now.
425 Too Early The server will not risk processing a possibly replayed request.
426 Upgrade Required The client must switch protocol, e.g. to TLS.
428 Precondition Required The server wants a conditional request to avoid lost updates.
429 Too Many Requests Rate limited. Slow down; check the Retry-After header.
431 Request Header Fields Too Large The headers are too big — often an oversized cookie.
451 Unavailable For Legal Reasons Blocked for legal reasons, such as a court order.
500 Internal Server Error The server hit an unhandled problem. Check the server error log.
501 Not Implemented The server does not support the functionality required.
502 Bad Gateway A proxy got an invalid response from the server behind it.
503 Service Unavailable Temporarily down — overloaded or in maintenance. Try again later.
504 Gateway Timeout A proxy waited too long for the server behind it to answer.
505 HTTP Version Not Supported The HTTP version used in the request is not supported.
507 Insufficient Storage The server has run out of space to complete the request.
508 Loop Detected The server detected an infinite loop while processing.
511 Network Authentication Required You need to log in to the network — typical of captive Wi-Fi portals.
Codes in the 400s mean the request was at fault; 500s mean the server was. Defined by the IETF in RFC 9110 and related standards.