Complete reference of all HTTP status codes with descriptions. Search by code or name to find what you need instantly.
HTTP status codes are grouped into five categories based on the first digit. 1xx codes are informational responses. 2xx codes indicate success. 3xx codes indicate redirection. 4xx codes indicate client errors - problems with the request. 5xx codes indicate server errors - problems on the server side.
200 OK is the standard success response. 301 Moved Permanently is used for permanent redirects. 302 Found is used for temporary redirects. 400 Bad Request means the server could not understand the request. 401 Unauthorized means authentication is required. 403 Forbidden means access is denied. 404 Not Found is returned when a resource does not exist. 500 Internal Server Error is a generic server error. 503 Service Unavailable means the server is temporarily unable to handle requests.
401 Unauthorized means the request lacks valid authentication credentials. The user needs to log in. 403 Forbidden means the server understood the request and the user may be authenticated, but they do not have permission to access the resource.
301 is a permanent redirect. Search engines update their index to point to the new URL and pass link equity. 302 is a temporary redirect. Search engines keep the original URL in their index. Use 301 when permanently moving a page and 302 when the redirect is temporary.
504 Gateway Timeout means a server acting as a gateway did not receive a timely response from an upstream server. This often happens when a backend service is slow or unresponsive. It is a server-side issue not caused by the client.