The HTTP Status Code Reference is a comprehensive, searchable guide to all standard HTTP response status codes defined by the IANA and major RFCs. HTTP status codes are three-digit numbers returned by web servers to indicate the result of a client's request — whether it succeeded, redirected, failed due to a client error, or encountered a server problem. They are grouped into five classes: 1xx (informational), 2xx (success), 3xx (redirection), 4xx (client error), and 5xx (server error). Understanding these codes is essential for web developers, API designers, DevOps engineers, and anyone debugging network issues. This reference includes the official code name, a plain-English description of what each code means, when it is correctly used, and common real-world scenarios where you are likely to encounter it — from the ubiquitous 404 Not Found to the more obscure 451 Unavailable For Legal Reasons.
Use the search box to filter by code number, name, or keyword. Browse by class category (2xx, 3xx, 4xx, 5xx) using the filter tabs. Click on any entry to expand its full description, usage guidance, and notes about browser or server behavior associated with that code.