ipnLog = TRUE; // Specify your authorize login and secret $my2CO->setSecret('YOUR_SECRET_KEY'); // Enable test mode if needed $my2CO->enableTestMode(); // Check validity and write down it if ($my2CO->validateIpn()) { file_put_contents('2co.txt', 'SUCCESS'); } else { file_put_contents('2co.txt', "FAILURE\n\n" . $my2CO->ipnData); }