Complete reference for all HTTP response status codes — 1xx to 5xx. Search by code number or keyword.
This HTTP status code reference is a fast, searchable list of every standard HTTP response code from 1xx to 5xx, each paired with its official name and a plain-English explanation of what it means and when a server sends it.
HTTP status codes are the three-digit numbers a web server returns with every response, telling the client how the request was handled. The first digit groups them into five families: 1xx informational, 2xx success, 3xx redirection, 4xx client errors, and 5xx server errors. Knowing the difference between a 301 and a 302, a 401 and a 403, or a 404 and a 410 can save hours of debugging and prevent SEO mistakes that quietly cost traffic. Rather than digging through the RFCs or scattered blog posts, this reference puts the whole catalogue in one place — type a number like 404, a keyword like "redirect", or a phrase like "unauthorized" and the matching codes appear instantly, colour-coded by family. People use it to:
Everything runs locally in your browser — the full code list is built into the page, so searching and filtering work instantly with nothing uploaded to any server and no tracking of what you look up. It works offline once loaded and stays just as quick whether you are checking a single code or scanning a whole family. Use it as a quick desk reference while developing, testing, or learning how the web really talks under the hood.
301 is a permanent redirect (clients should update bookmarks/links). 302 is temporary (clients should keep using the original URL).
401 means "not authenticated — please log in". 403 means "authenticated but not allowed to access this resource".
Not always — 201 Created for new resources after POST, 204 No Content for successful DELETEs, 202 Accepted for async jobs.
The first digit groups every status code into a family. 1xx is informational (the request was received and processing continues), 2xx is success (the request was understood and accepted), 3xx is redirection (further action such as following a new URL is needed), 4xx is a client error (the request was bad or unauthorised), and 5xx is a server error (the server failed to fulfil a valid request).
404 Not Found means the server could not find the requested resource, with no statement about whether it ever existed or might come back. 410 Gone is more specific — it tells clients and search engines the resource was deliberately removed and will not return, so they can drop it from indexes and bookmarks rather than retrying.
301 Moved Permanently signals that a resource has moved for good, so clients should update links and search engines should transfer ranking to the new URL. 302 Found is a temporary redirect — the original URL should keep being used because the move is expected to be short-lived. Use 301 for permanent migrations and 302 for temporary detours like maintenance pages.
500 Internal Server Error is a generic message that the server hit an unexpected condition and could not complete the request — the fault is on the server side, not with your request. It usually points to an unhandled exception, a misconfiguration, or a bug in the application code, and the real cause is typically found in the server logs rather than the response itself.