Checkout Flow

The checkout link is a secure, hosted payment page where customers complete their cryptocurrency payments. Each link is unique, signed, and has configurable expiration times.

Checkout URL Structure

https://yourdomain.com/checkout/{paymentId}?expires={timestamp}&signature={hmac}&redirectUrl={encoded_url}

Security

Each checkout URL includes a cryptographic signature:

signature = HMAC-SHA256(
  key: APP_KEY,
  message: "{paymentId}|{expires}"
)

• The signature is validated on each request
• Expired links are rejected
• Tampering with any URL component invalidates the signature

Checkout links expire based on the expiresAt parameter passed during payment creation. If not specified, the default is 1 year from creation.

Checkout Flow

stateDiagram-v2
    [*] --> Loading: Customer opens checkout URL
    Loading --> CurrencySelection: Payment loaded (OPEN)
    CurrencySelection --> PaymentInstructions: Currency selected
    PaymentInstructions --> FOUND: Funds detected on blockchain
    FOUND --> RECEIVED: Confirmations met
    RECEIVED --> CONFIRMED: Payment confirmed
    CONFIRMED --> [*]: Redirect to merchant

Customer Experience

1. Currency Selection — choose from merchant's configured cryptocurrencies
2. Payment Instructions — QR code, address, and exact amount to send
3. Payment Monitoring — real-time transaction detection and confirmation tracking
4. Completion — redirect to merchant's success URL

Embedding

You can embed the checkout page in an iframe:

<iframe
  src="https://yourdomain.com/checkout/550e8400-...?expires=...&signature=..."
  width="100%"
  height="600"
  frameborder="0"
  allow="clipboard-write"
></iframe>

Troubleshooting

Next Steps

• Check payment status
• Handle payment webhooks
• Process refunds