What the numbers mean

When your browser asks a server for a page, the reply includes a status code. The first digit gives the broad result:

  • 1xx: The server has received the request and sent an early update.
  • 2xx: The request succeeded. 200 means success; 201 means something was created.
  • 3xx: Another step is needed. 301 points to a new address; 304 means a saved copy can be used.
  • 4xx: There is a problem with the request or access. 404 means the page was not found.
  • 5xx: The server could not complete the request. 500 is a general server error.

The number is only a starting point

401 means valid sign-in details are missing; 403 means the server refuses access. A 200 says the request succeeded, but the information returned could still be wrong. When something fails, the reply can also explain why.