Status code

Also written: status codes, HTTP status, 200, 201, 400, 401, 403, 404, 409, 429, 500, 503

The number that starts an HTTP response: 2xx success, 4xx the client's mistake, 5xx the server's problem. Common ones: 200 OK, 201 Created, 400 Bad Request, 401 Unauthorized (not logged in), 403 Forbidden (not allowed), 404 Not Found, 409 Conflict, 429 Too Many Requests, 500 Internal Server Error, 503 Service Unavailable.