HTTP Status Codes

HTTP status codes are three-digit numbers returned by a server in response to a client request. They are grouped into five classes:

• 1xx Informational – Request received, continuing process.
• 2xx Success – Request was successfully received, understood, and accepted.
• 3xx Redirection – Further action needs to be taken 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.

Status codes are defined primarily in RFC 9110 (HTTP Semantics) and extended by other RFCs and standards such as WebDAV.