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ToolWrenLook up what any HTTP status code means — by number, by keyword, or by class (1xx–5xx) — with a clear description for each.
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404), a keyword (e.g. not found), or a class wildcard (e.g. 5xx).Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.
Every HTTP response carries a three-digit status code that tells the client how the request went. They are grouped into five classes: 1xx informational, 2xx success, 3xx redirection, 4xx client errors and 5xx server errors.
Type a code (like 404), a keyword (like 'not found'), or a class wildcard (like 5xx) to see matching codes with their official reason phrase and a friendly explanation.
200 OK, 301 permanent redirect, 401 unauthorized, 403 forbidden, 404 not found, 429 too many requests, 500 server error and 503 service unavailable are the ones you will meet most.
Every HTTP response carries a three-digit status code that tells the client how the request went. This lookup explains any code - by number, by keyword, or by class - with its official reason phrase and a plain-English description, so you can quickly understand what a server or API is telling you.
Status codes are grouped by their first digit. 1xx are informational, 2xx mean success (200 OK, 201 Created), 3xx are redirection (301 Moved Permanently, 304 Not Modified), 4xx are client errors - something wrong with the request (400, 401, 403, 404), and 5xx are server errors - the server failed to fulfil a valid request (500, 502, 503).
A handful dominate everyday work: 200 OK, 301/302 redirects, 304 Not Modified (served from cache), 400 Bad Request, 401 Unauthorized (not authenticated), 403 Forbidden (authenticated but not allowed), 404 Not Found, 429 Too Many Requests (rate-limited), and 500/502/503 server errors.
Reading status codes is essential for debugging APIs and websites - they pinpoint whether a problem is the client's request or the server. They also matter for SEO: search engines treat 301 (permanent) and 302 (temporary) redirects differently, index 200 pages, drop 404s, and a spike in 5xx errors can harm rankings. Knowing the codes helps you keep a site healthy.
Type a code like 404, a keyword like 'not found', or a class wildcard like 5xx to see matching codes with descriptions. It is a quick reference for developers, testers and SEOs. Everything runs in your browser.