status code

Also written: HTTP status codes, HTTP status, 200, 404, 301, 302, 5xx

The three-digit number in a web server's reply: 200 OK, 301 or 302 moved (the Location: header says where), 404 no such page, and 500 to 599 (5xx) the server itself failed. Any code at all proves the network path works; 4xx and 5xx are the application's problem.