What is HTTP status codes?

Status codes are issued by a server in response to a client’s request made to the server.

There are five in number where are following:

1xx informational response – the request was received, continuing process
2xx successful – the request was successfully received, understood, and accepted
3xx redirection – further action needs to be taken in order to complete the request
4xx client error – the request contains bad syntax or cannot be fulfilled
5xx server error – the server failed to fulfil an apparently valid request

Each status code has unique purpose and provides specific information.