<?php 
$API_KEY='81dce78f-8f75-429b-938c-de8f82ac8f97'
$data=array(
    "url_callback"=>"http://127.0.0.1:3000/payment-callback",
    "currency"=>"USD",
    "network"=>"TRON",
    "order_id"=>"1728672470642",
    "status"=>"paid",
    "uuid"=>"d29b55f3-3b26-4657-a573-b9a2a9537f4e"
);
$data = json_encode($data);
$sign = md5(base64_encode($data) . $API_KEY);