FastUSDT Pay API Reference

FastUSDT Pay provides a modern RESTful API to accept USDT deposits on TRON (TRC20) and Binance Smart Chain (BEP20). All API endpoints accept and return JSON.

Base API URL: http://fastusdtpay.damanplay.site/api/v1/

2. Authentication

To authenticate requests, obtain your API Key and Secret Key from your Merchant Portal. Pass your API Key in the JSON request body as api_key or as an HTTP Header:

X-API-KEY: fup_key_your_public_api_key

POST

/api/v1/create_order.php

Create a new USDT payment invoice for your customer.

Request Body Parameters

Field	Type	Required	Description
api_key	string	Yes	Your merchant API Key
merchant_order_id	string	Yes	Unique invoice/order ID from your database (e.g. ORD_1029)
amount	float	Yes	Deposit amount in USDT (e.g. 50.00)
currency	string	No	`USDT.TRC20` (default) or `USDT.BEP20`
customer_id	string	No	User ID in your system

PHP Integration Example (Ready to copy)

<?php
$payload = [
    'api_key'           => 'YOUR_API_KEY_HERE',
    'merchant_order_id' => 'ORD_' . time(),
    'amount'            => 10.00,
    'currency'          => 'USDT.TRC20',
    'customer_id'       => 'USER_123'
];

$ch = curl_init('http://fastusdtpay.damanplay.site/api/v1/create_order.php');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
$response = curl_exec($ch);
curl_close($ch);

$result = json_decode($response, true);
if ($result && $result['success']) {
    // Redirect user to FastUSDT Pay checkout page:
    header("Location: " . $result['data']['checkout_url']);
    exit;
} else {
    echo "Error: " . $result['message'];
}
?>

5. Verifying Instant Webhooks

When an on-chain deposit is detected and confirmed, FastUSDT Pay sends an HTTP POST request to your merchant Callback URL. Every request includes an X-FUP-Signature header generated using HMAC-SHA256 with your Secret Key.

Webhook Listener Sample (PHP)

<?php
$secretKey = 'YOUR_SECRET_KEY_HERE';

// 1. Get raw request body and signature header
$rawBody = file_get_contents('php://input');
$receivedSignature = $_SERVER['HTTP_X_FUP_SIGNATURE'] ?? '';

// 2. Compute expected HMAC-SHA256 signature
$expectedSignature = hash_hmac('sha256', $rawBody, $secretKey);

// 3. Verify signature
if (!hash_equals($expectedSignature, $receivedSignature)) {
    http_response_code(403);
    die('Invalid webhook signature');
}

$data = json_decode($rawBody, true);

if ($data['status'] === 'PAID') {
    $merchantOrderId = $data['merchant_order_id'];
    $amountPaid = $data['amount_usdt'];
    $txid = $data['txid'];

    // TODO: Update your database and credit user wallet here!
    // Example: $db->query("UPDATE users SET balance = balance + $amountPaid WHERE id = '{$data['customer_id']}'");

    http_response_code(200);
    echo json_encode(['status' => 'success']);
    exit;
}
?>