$url = "http://steempay.io/payment/verify?payid=" . $_GET['success'] . "& receiver=YOUR_USERNAME&amount=1.000¤cy=SBD";
$json = file_get_contents($url);
if (json_decode($json->status) && json_decode($json->success) == "success")
{
// Payment is double verified, do whatever needed now.
}
}else{
// Some error occured
echo $_GET['message'];
}