When we visit a (web) site, it usually send some request to the server. There will be a returned code to indicate the status (etc Successful). This is called the Hypertext Transfer Protocol (HTTP). The current standard is HTTP/1.1 standard (RFC 7231) unless it is stated otherwise.
Below are the list of status codes. They are classified into 5 classes :
- 1xx Informational — 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 a valid request
