StatusCode

Statuscode is a term used in computing to denote a numeric code that conveys the result or state of a operation, response, or transaction. In networking and web contexts, status codes are part of protocol messages that travel between a client and a server. They help indicate whether a request was successful, redirected, or resulted in an error, and they often guide the client on subsequent actions.

The most widely known set of status codes comes from the Hypertext Transfer Protocol (HTTP). HTTP status codes are three-digit integers, generally grouped by their first digit: 1xx (informational), 2xx (success), 3xx (redirection), 4xx (client error), and 5xx (server error). They are typically accompanied by a reason phrase that briefly describes the result. Common examples include 200 OK, 201 Created, 204 No Content; 301 Moved Permanently, 302 Found; 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found; and 500 Internal Server Error, 503 Service Unavailable. In RESTful APIs and web services, these codes standardize how clients interpret responses and decide on retries, authentication, or data handling.

Other communication protocols also define status codes, such as FTP, SMTP, SIP, and various application-layer protocols. Each protocol uses its own set of codes and meanings, though the general purpose is similar: signaling the outcome of a request and any required client action. Some environments allow custom or extended codes to provide additional detail for specific applications.

Beyond network protocols, the term status code can also refer to exit codes from programs in operating systems, where 0 typically indicates success and non-zero values indicate various failure conditions.