HTTP Status Code

An HTTP Status Code is a three-digit number that is returned by a web server along with any additional response data in response to a given request. The HTTP Status Code is meant to provide information on the outcome of the request, giving an indication of whether the request was successful, resulted in an error, or requires further action.

There are 5 base categories for HTTP Status Codes, represented by the first number in the 3-diget code:

• 1xx - Informational: These status codes indicate that the server has received the request and are often an interim response.
• 2xx - Success: These status codes indicate that the request was received, understood, and accepted, with the most common code in this group being '200 OK'.
• 3xx - Redirection: These status codes indicate that further action must be taken in order to complete the request (usually handled automatically by a web browser, such as in the case of a 301 redirect where the browser will proceed to load the new URL indicated by the 301 response).
• 4xx - Client Error - These status codes indicate an error on the client's side. These codes often mean that the server recieved and processed the request, but what was requested either doesn't exist (such as a 404 Not Found) or is blocked by the server (such as a 403 Forbidden).
• 5xx - Server Error - These status codes indicate an error on the server's side. These codes can often occur when there is an error in server side code (such as PHP) that is not handled correctly and results in an unrecoverable error (giving a 500 Internal Server Error response code), or when there is a server issue such as being overloaded or down for maintenance (giving a 503 Service Unavailable response code)