if (!$fp) { // HTTP ERROR else { fputs ($fp, $header . $req); while (!feof($fp)) { $res = fgets ($fp, 1024); if (strcmp ($res, "VERIFIED") == 0) { // check the payment_status is Completed // check that txn_id has not been previously processed // check that receiver_email is your Primary PayPal email // check that payment_amount/payment_currency are correct // process payment } else if (strcmp ($res, "INVALID") == 0) { // log for manual investigation } } fclose ($fp); } ?>