Status-Code
An HTTP Status-Code is a three-digit integer returned by a Server to a Client to indicate the outcome of a specific Hypertext Transfer Protocol (HTTP) request. These codes are essential for the functioning of the World Wide Web, providing a standardized way for machines to communicate success, redirection, or error states. The primary authority for these codes is the Internet Assigned Numbers Authority (IANA), which maintains the official registry based on specifications from the Internet Engineering Task Force (IETF), most notably RFC 7231.
Categorization
The first digit of the Status-Code defines the class of the response:
- 1xx (Informational): The request was received, continuing process.
- 2xx (Successful): The request was successfully received, understood, and accepted. A common example is 200 OK.
- 3xx (Redirection): Further action needs to be taken by the User-Agent to complete the request.
- 4xx (Client Error): The request contains bad syntax or cannot be fulfilled. The most famous is 404 Not Found.
- 5xx (Server Error): The Server failed to fulfill an apparently valid request, such as the 500 Internal Server Error.
Developers and system administrators rely on these codes for Debugging and monitoring API performance. Detailed documentation on individual codes can be found on the MDN Web Docs or the official IANA HTTP Status Code Registry.