HTTP status code

An HTTP status code is a three-digit number in a server's response that summarizes what happened to a request. A browser or other client uses the code to decide whether the request succeeded, whether it should try another address, or whether it needs to show an error. The response may also include explanatory text or page content.

What do the first digits mean?

The first digit places the response in a broad class:

• 1xx — informational; the request is still being handled.
• 2xx — successful; the request was received and accepted.
• 3xx — redirection; the client may need to make another request.
• 4xx — client error; the request could not be fulfilled because of an issue such as a missing page or insufficient permission.
• 5xx — server error; a server failed to complete an apparently valid request.

For example, 200 means the request succeeded, 301 says the resource has moved permanently, and 404 means the requested resource was not found. The 403 code indicates that the server understood the request but refuses to fulfill it. A 503 means the service is temporarily unavailable. Each code has a specific definition; the first digit is a helpful summary, not a complete diagnosis.

Does a status code explain the whole problem?

No. The code describes the response to one HTTP request. It does not necessarily explain why the server sent that response, and a site's own error page may display a different message. A 404 response, for example, can mean the page is missing or that the server is configured to hide it. A 5xx response tells the client that a server-side failure occurred, but the site operator may need logs to find the cause.

For example, if Jamie opens /old-menu and gets 404, the server has answered, but it says that it cannot find that resource. Jamie can try the site's navigation or a current link. If the response is 503, the page may be temporarily unavailable and a later retry could work. The result does not by itself prove that the entire domain or network is down.

Related terms

• HTTP — the protocol that carries requests and status responses
• 404 Not Found — a response saying the requested resource was not found
• 403 Forbidden — a response refusing access to the requested resource
• 5xx server errors — responses indicating server-side failure