<button
    data-spankpay-key="test_quickstart_key"
    data-amount="69.69"
    data-currency="USD"
    data-callback-url="https://pay-api.spankchain.com/quickstart/callback"
    data-metadata="{}"
    data-description="Test Invoice HTML"
    data-accepted-currencies="ETH,BTC">
  Pay with SpankPay!
</button>

<script src="https://pay.spankchain.com/spankpay.js"></script>