HTTP Status Code Reference
Every standard registered HTTP status code, searchable and grouped by class, with common causes and RFC references.
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Which code should I use?
How to look up an HTTP status code
- Type a code such as 404, or a word such as “redirect” or “rate limit”.
- Or filter by class: 1xx, 2xx, 3xx, 4xx or 5xx.
- Read what the code means, its common causes and the RFC that defines it.
About this tool
This list covers every status code in the IANA HTTP Status Code Registry as of RFC 9110 (the current HTTP Semantics specification) plus the long-standing WebDAV extensions (RFC 4918, RFC 5842) and a handful of individually-registered codes (rate limiting in RFC 6585, 451 Unavailable For Legal Reasons in RFC 7725, 425 Too Early in RFC 8470, 103 Early Hints in RFC 8297). Nothing here is invented or vendor-specific — codes like 419, 420, 430, or 440 that you might see from a particular framework or CDN are not part of any standard and are deliberately left out.
Each entry's "common causes" line describes the situations that typically produce that status in practice — useful when you're staring at a code in a network tab and trying to work out which layer (browser, your app, a proxy, or the origin server) is responsible. The RFC citation is the formal definition, if you want the precise wording.
Search matches against the code number, name, description, and causes text, so searching "teapot" finds 418 and searching "cache" finds 304 and other caching-related codes. Nothing you type is sent anywhere — this is a static reference rendered entirely in your browser.
Questions about HTTP status codes
What is the difference between 401 and 403?
401 Unauthorized means you need to log in or your credentials were wrong. 403 Forbidden means the server knows who you are but won’t let you in.
What is the difference between 301 and 302?
301 is a permanent redirect, which search engines follow and pass ranking to. 302 is temporary, so the original address stays the one to index.
What do 502 and 503 mean?
502 Bad Gateway: a proxy or load balancer got a bad response from the server behind it. 503 Service Unavailable: the server is overloaded or down for maintenance.
What does 429 mean?
Too Many Requests: you’ve hit a rate limit. Wait, often for the time in the Retry-After header, before trying again.
Why aren’t codes like 419 or 420 listed?
They’re used by particular frameworks or services but aren’t part of any standard, so they’re left out.