Status code
Also written: HTTP status, HTTP status codes, 200, 201, 204, 400, 404, 409, 500, 503
The number in an HTTP response that says how the request went: 200s mean success, 400s a client mistake, and 500s a server problem. Common ones are 200 OK, 201 Created (new resource), 204 No Content (OK, empty body), 400 Bad Request (bad data), 404 Not Found, 409 Conflict (clashes with current state), 500 Internal Server Error (a bug) and 503 Service Unavailable (such as a health check reporting DOWN).