HTTP status codes are three-digit numbers returned by a server in response to a client’s request, indicating the status of the request. They are grouped into five classes:
- 1xx (Informational): The request was received, and the process is continuing.
- 2xx (Success): The request was successfully received, understood, and accepted.
- 3xx (Redirection): Further action must be taken to complete the request.
- 4xx (Client Error): The request contains bad syntax or cannot be fulfilled due to client-side issues.
- 5xx (Server Error): The server failed to fulfill a valid request due to server-side issues.