HTTP status codes are the response codes supplied by the web servers against any HTTP request. These codes are 3-digit integer values where the first digit of the code specifies one of five classes of response. There are different series of HTTP status codes. Each status code series have their own status category and each status code has a specific meaning.
1xx = Informational – It means the request has been received and the process is continuing.
2xx = Success – It means the action was successfully received, understood, and accepted.
3xx = Redirection – It means further action must be taken in order to complete the request.
4xx = Client Error – It means the request contains incorrect syntax or cannot be fulfilled.
5xx = Server Error – It means the server failed to fulfill an apparently valid request.
All the HTTP status codes are a part of the HTTP/1.1 standard. The Internet Assigned Numbers Authority (IANA) maintains the official registry of the HTTP status codes.