HTTP status codes

Also written: Status code, status codes, 200, 201, 204, 400, 401, 403, 404, 409, 415, 500, 503

The number in a response saying how it went: 2xx is success, 4xx means the caller made a mistake and 5xx means the server did. Common codes are 200 OK, 201 Created, 204 OK with no body, 400 bad input, 401 not signed in, 403 signed in but not allowed, 404 not found, 409 conflict with existing data, 415 unsupported media type, 500 server failed and 503 service unavailable.