RapidPay (v1/checkout-pay)

<?php
declare(strict_types=1);
// rapid_pay.php — plain PHP: call v1/checkout-pay, then print a page with rapid.js.
// Configure: API base, secret API key (rc_sk_...), HTTPS origin (must match intended_domain), and the payer email.

$apiBase = rtrim(getenv('RAPIDCENTS_API_BASE') ?: 'https://api.rapidcents.com', '/');
$apiKey  = getenv('RAPIDCENTS_API_KEY') ?: 'rc_sk_YOUR_SECRET_API_KEY';
$origin  = getenv('RAPIDCENTS_HTTPS_ORIGIN') ?: 'https://your-site.example';

$body = [
    'customer_email'  => 'payer@example.com',
    'amount_subtotal' => 20.0,
    'amount_total'    => 20.0,
    'amount_tax'      => 0.0,
    'amount_discount' => 0.0,
    'surcharge'       => false,
    'description'     => 'Order',
];

$endpoint = $apiBase . '/api/v1/checkout-pay';
$ch = curl_init($endpoint);
curl_setopt_array($ch, [
    CURLOPT_POST           => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER     => [
        'Authorization: Bearer ' . $apiKey, // rc_sk_... secret API key
        'Content-Type: application/json',
        'Accept: application/json',
        'Origin: ' . $origin, // Must match API key's intended_domain
    ],
    CURLOPT_POSTFIELDS     => json_encode($body),
]);
$raw  = curl_exec($ch);
$code = (int) curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

if ($raw === false || $code < 200 || $code >= 300) {
    http_response_code(500);
    echo 'v1/checkout-pay failed (HTTP ' . $code . ')';
    exit;
}

$data      = json_decode($raw, true) ?: [];
$session   = $data['checkout_session'] ?? [];
$payUrl    = $data['iframe_url'] ?? $data['checkout_url'] ?? $session['iframe_url'] ?? $session['checkout_url'] ?? '';
$scriptSrc = $apiBase . '/js/rapid.js';

if ($payUrl === '') {
    http_response_code(500);
    echo 'No checkout URL in API response.';
    exit;
}
?><!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Rapid checkout</title>
  <meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
  <div class="w-full">
    <script
      src="<?= htmlspecialchars($scriptSrc, ENT_QUOTES, 'UTF-8') ?>"
      data-checkout-url="<?= htmlspecialchars($payUrl, ENT_QUOTES, 'UTF-8') ?>"
      data-height="min(720px, 90vh)"
    ></script>
  </div>
</body>
</html>