The HTTP protocol defines five classes of response codes to indicate the status of a request:
- 1XX-Informational: The 100 range codes are used for informational purposes. It is only present in HTTP/1.1.
- 2XX-Success: The 200 range of codes are used to indicate that the action requested by the client was received, understood, accepted, and processed. The most common is 200 OK.
- 3XX-Redirection: The 300 range indicates the client that must take additional actions to complete the request. Most of these codes are used in URL redirection. The most common of this group is the 302 Found code.
- 4XX-Client-side error: The 400 range are used to indicate that the client has had an error. The most common is 404 Not Found.
- 5XX-Server-side error ...