$ch = curl_init("https://service.payizone.com/token");
$payload = json_encode( array( "app_id"=> 'Müşteri APP ID', "app_secret" => "Müşteri APP SECRET" ) );
curl_setopt( $ch, CURLOPT_POSTFIELDS, $payload );
curl_setopt( $ch, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));
curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
$result = curl_exec($ch);
curl_close($ch);
$result = json_decode($result);