The fastest HTTP status code reference
AG HTTP is a free tool to instantly search and look up the HTTP response status codes you often run into during development and debugging, with no sign-up or installation.
On the home page you can search in real time by code number, name, or description, and clicking a code takes you to a dedicated page with its meaning, when it occurs, common causes, fixes, related codes, and RFC reference. It covers about 62 codes, from the standard codes across the five classes 1xx–5xx to WebDAV and extension codes.
Frequently confused topics such as 301 vs 302, 401 vs 403, and 4xx vs 5xx are organized into separate guides, and you can view related codes grouped together on the per-class hub pages.
All data is statically included inside your browser, so no input or search value is ever sent to or stored on a server.
A provisional response signaling that the request was received and processing is continuing. It is sent before the final response.
Means the request was successfully received, understood, and processed. 200 OK is the classic example.
Further action, usually moving to another URL, is needed to complete the request. 301 and 302 are the classic examples.
A client-side problem such as a malformed request or insufficient permissions. 400, 401, 403, and 404 are the classic examples.
The server failed to fulfill a valid request. 500, 502, and 503 are the classic examples.
401 Unauthorized means 'not authenticated,' indicating that login or credentials are required, while 403 Forbidden means you are authenticated but don't have permission for that resource. 403 is not resolved by logging in again.
301 Moved Permanently is a permanent move, so search engines transfer link equity to the new URL, while 302 Found is a temporary move that keeps using the original URL. If you need to preserve the method, use 308 or 307.
HTTP reason phrases (OK, Not Found, etc.) are English by RFC spec and are the convention in developer references. The on-screen guidance and descriptions are translated into each language, but the code names and technical descriptions keep their canonical English.
No. All status code data is statically included in the browser, and no value, including your search terms, is ever sent to or stored on a server.