Every HTTP status code, what it means, when to send it and the RFC it comes from
Runs in your browser. Nothing you type is sent anywhere. Updated on 25 Oct 2026.An HTTP status code says what happened in 3 digits. 404 means the thing was never there, 410 means it was and is gone for good, and 301 moves it permanently. Every code is listed here with when to send it and the RFC that defines it.
Type a number, a name or what you want to say, such as "rate limit", into the search box.
Narrow the Codes list with the Show chips: Common, All, or one class from 1xx to 5xx.
Select a code to read its meaning, when to use it, whether it is cacheable and the RFC that defines it.
Choose a language under "Send this code in" and press Copy snippet to take the code that returns it.
This HTTP status codes reference lists every registered code from 100 to 511, plus the unregistered ones that nginx, Apache, Laravel and Cloudflare return. Each entry says what the code actually means, when to send it, whether a cache may store the response without cache headers, whether a redirect changes the request method, and which RFC defines it.
Search works three ways. Type a number such as 404, or a class such as 4xx, to jump straight to it. Type a name such as "not found". Or describe what you want to express, and the intent search finds the code: "login failed" gives 401, "rate limit" gives 429, "file too large" gives 413, "validation failed" gives 422.
Two details most lists get wrong are included here. Cacheability is not a yes or no: RFC 9110 section 15.1 names twelve codes a cache may store with no explicit headers at all, which is why an accidental 404 can stick. And redirects differ: 301 and 302 let a client turn a POST into a GET, 303 always does, while 307 and 308 must repeat the method and body exactly.
Every common code comes with a copyable snippet for raw HTTP, Express, Fastify, FastAPI, Go and PHP, including the header that code requires, such as WWW-Authenticate on a 401 or Allow on a 405. Nothing is sent anywhere; the whole table is in the page.
Use 401 Unauthorized. It means the server does not know who you are, so a missing, expired or wrong credential belongs there. Use 403 Forbidden only when you know who the caller is and are still refusing. The specification wants a WWW-Authenticate header on every 401.
401 means unauthenticated: send credentials and try again. 403 means authenticated but not allowed: better credentials will not help. If revealing that a record exists is itself a leak, some APIs answer 404 instead of 403 so an attacker learns nothing.
RFC 9110 section 15.1 lists 200, 203, 204, 206, 300, 301, 308, 404, 405, 410, 414 and 501 as heuristically cacheable, and RFC 7725 adds 451. A cache may store those with no Cache-Control or Expires header, which is why a temporary 404 can persist. Every other code needs explicit cache headers.
The specification does not allow it, but nearly every browser does exactly that for 301 and 302. A 303 always turns the next request into a GET. If the method and body must survive the redirect, use 307 for a temporary move or 308 for a permanent one.
418 I'm a Teapot comes from RFC 2324, an April Fools' joke from 1998 about a coffee pot protocol. A 2017 proposal to reuse the number was withdrawn after objections, so it stays reserved in the IANA registry and must never be used for a real meaning.
No. 499 is an nginx log-only code for a client that hung up, and 520 to 527 are Cloudflare codes for problems between the edge and your origin. None are registered with IANA. They are listed here because you will meet them in logs, each marked with the product that invented it.
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