HTTP Status Code Lookup

The first digit sets the class. 1xx is informational, 2xx is success, 3xx is redirection, 4xx is a client error, and 5xx is a server error. So a 404 is a client error you can often fix by correcting the request, while a 503 is a server error you usually cannot fix from the client side.

Yes. Type part of a reason phrase, such as forbidden, timeout, or gateway, and the tool lists every code whose name contains that text. The match is case-insensitive, so uppercase and lowercase both work.

If you type digits, the tool matches any code whose number begins with them. Typing 4 lists the whole 4xx family, typing 42 narrows it to 421 through 429, and typing a full code like 404 returns just that one. This is a quick way to browse an entire class.

A 401 Unauthorized means the request lacks valid authentication, so signing in or sending a correct token may resolve it. A 403 Forbidden means you are recognised but not permitted to access the resource at all, so better credentials will not help unless your permissions change.

Both are gateway errors reported by a proxy or load balancer sitting in front of your app. A 502 Bad Gateway means the upstream server returned an invalid or empty response, while a 504 Gateway Timeout means the upstream server did not reply within the allowed time.

It began as an April Fools' joke in the Hyper Text Coffee Pot Control Protocol, yet many servers and frameworks implement it, so it is widely recognised and included here. It is not part of the core HTTP standard and should not be used for real error handling.

It covers the standard IANA registry: the 1xx, 2xx, 3xx, 4xx, and 5xx ranges from RFC 9110 and related specs, plus commonly deployed WebDAV codes such as 207 Multi-Status and 423 Locked. Vendor-specific codes like Cloudflare's 5xx extensions are not part of the standard set and are not listed.

No. The full code table is bundled with the page and the search runs in your browser, so nothing is sent to a server and lookups work offline once the page has loaded.

If your query is a number that is not in the standard registry, such as 499 or a vendor-only code, no card appears because the tool only lists official codes. Check the number, or search by a partial reason phrase instead.