Application that we developed sometime unexpectedly show error message or some time during debugging need to identify the status of the request. To identify the type of error or response status codes very first thing will see the error code returned by the page. Based on the response status code we can narrow down the error type or identify the status of the request like Success/failure.
Basically we can group the response status code in 4 different types
1) Informational (1XX)
2) Success (2XX)
3) Redirection (3XX)
4) Client (4XX)
Each group have different type of status code for more you can reffer here