Examples

E-commerce Checkout (Backend)

import express from 'express';
import { createCheckout } from '@zkp2p/pay-sdk';

const app = express();
app.use(express.json());

const zkpayConfig = {
  apiBaseUrl: process.env.ZKPAY_API_URL!,
  checkoutBaseUrl: process.env.ZKPAY_CHECKOUT_URL!,
  apiKey: process.env.ZKPAY_API_KEY!,
};

app.post('/api/checkout', async (req, res) => {
  const { orderId, amount, customerId } = req.body;

  try {
    const checkout = await createCheckout(
      {
        requestedUsdcAmount: Number(amount).toFixed(2),
        destinationChainId: 8453,
        destinationToken: 'USDC',
        destinationAddress: process.env.WALLET_ADDRESS,
        successUrl: `${process.env.APP_URL}/order/${orderId}/success`,
        cancelUrl: `${process.env.APP_URL}/cart`,
        notes: { orderId, customerId },
      },
      zkpayConfig,
    );

    res.json({
      checkoutOrderId: checkout.order.id,
      checkoutUrl: checkout.checkoutUrl,
    });
  } catch {
    res.status(500).json({ error: 'Failed to create order' });
  }
});

Frontend Redirect

function CheckoutButton({ orderId, amount, customerId }) {
  const handleCheckout = async () => {
    const response = await fetch('/api/checkout', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ orderId, amount, customerId }),
    });

    const { checkoutUrl } = await response.json();
    window.location.href = checkoutUrl;
  };

  return <button onClick={handleCheckout}>Pay</button>;
}

Onramp Into User Wallet

const checkout = await createCheckout(
  {
    requestedUsdcAmount: '100.00',
    destinationChainId: 8453,
    destinationToken: 'USDC',
    destinationAddress: userWalletAddress,
    successUrl: `${process.env.APP_URL}/onramp/success`,
    cancelUrl: `${process.env.APP_URL}/onramp`,
    notes: {
      type: 'onramp',
      userWallet: userWalletAddress,
    },
  },
  zkpayConfig,
);

Webhook Handler

import express from 'express';
import crypto from 'crypto';
import type { WebhookPayload } from '@zkp2p/pay-shared';

const app = express();

app.post('/webhooks/zkp2p', express.raw({ type: 'application/json' }), async (req, res) => {
  const signature = req.headers['x-webhook-signature'] as string;
  const timestamp = req.headers['x-webhook-timestamp'] as string;
  const payload = req.body.toString();

  const expectedSignature = crypto
    .createHmac('sha256', process.env.WEBHOOK_SECRET!)
    .update(`${timestamp}.${payload}`)
    .digest('hex');

  if (signature !== expectedSignature) {
    return res.status(401).send('Invalid signature');
  }

  const event = JSON.parse(payload) as WebhookPayload;
  res.status(200).send('OK');

  switch (event.type) {
    case 'ORDER_FULFILLED':
      await db.orders.update({
        where: { checkoutOrderId: event.data.order?.id },
        data: { status: 'paid' },
      });
      break;
    case 'PAYMENT_SETTLED':
      // Optional: record settlement telemetry, but do not mark order as paid here.
      break;
    case 'PAYMENT_FAILED':
    case 'PAYMENT_EXPIRED':
      await db.orders.update({
        where: { checkoutOrderId: event.data.order?.id },
        data: { status: 'failed' },
      });
      break;
  }
});