websystemer / Network / HTTP Status Codes
HTTP Status Codes: Meaning and When to Use Each
Look up any HTTP status code: what it means and when to send it, from 100 to 511 with IANA names. Includes 401 vs 403, 301 vs 308 and Cloudflare errors. Runs in your browser.
About HTTP Status Codeshow it works and good to know
The five classes
1xx informational, 2xx success, 3xx redirection, 4xx the client made a mistake, 5xx the server failed. A client that does not know a code treats it like the first code of its class, so an unknown 499 is handled as a 400.
The ones people mix up
401 or 403? 401 means "I do not know who you are", 403 means "I know who you are and the answer is no". 301 or 308? Both are permanent; 308 forces the client to keep the method and body. 400 or 422? 400 for a request that cannot be parsed, 422 for one that parses but breaks a rule. 502, 503 or 504? A proxy got garbage, the service is down or busy, or the upstream was too slow.
Sources
Names and numbers follow the IANA HTTP Status Code Registry and RFC 9110. A few widely seen codes that are not in the registry (nginx and Cloudflare) are marked with their source. Link straight to a code with #404 on the end of the address.
Privacy
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