Accept a Payment

Your server          Lyel Pay API           Your customer
    │                     │                      │
    │── POST /gateway ────▶│ Create intent        │
    │◀─ { sessionToken } ─│                      │
    │                     │                      │
    │── (send token) ─────────────────────────▶  │
    │                     │                      │
    │                     │◀── initOtp ──────────│
    │                     │──── OTP SMS ────────▶│
    │                     │                      │
    │                     │◀── verifyOtp (code) ─│
    │                     │                      │
    │                     │◀── charge ───────────│
    │                     │──── webhook ────────▶│ (your server)

// server.ts
import { LyelPay } from '@lyel/lyel-pay-node';

const lyel = new LyelPay(process.env.LYELPAY_SECRET_KEY!);

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

  const intent = await lyel.paymentIntents.create({
    amount: String(amount),
    currency: 'XAF',
    description: `Order #${orderId}`,
    metadata: { orderId, customerId },
  });

  // Return only what the frontend needs
  res.json({
    intentId: intent.id,
    sessionToken: intent.sessionToken,
    expiresAt: intent.expiresAt,
  });
});

// checkout.ts
import { LyelPay, OPERATION_TYPE_ENDPOINTS } from '@lyel/lyel-pay-js';

const lyel = new LyelPay({ apiKey: 'YOUR_API_KEY', env: 'production' });

async function startCheckout(userId: string, intentionId: string) {
  // Send OTP to the user
  await lyel.initOtp({ userId, channel: 'sms' });
  
  // Show OTP input to user, then:
  return async function confirmOtp(otp: string) {
    await lyel.verifyOtp({ userId, otp });
    const result = await lyel.charge({ intentionId });
    return result;
  };
}

// webhook.ts
app.post('/webhooks/lyelpay', express.raw({ type: 'application/json' }), async (req, res) => {
  const event = lyel.webhooks.constructEvent(
    req.body.toString(),
    req.headers['lyel-signature'] as string,
    process.env.LYELPAY_WEBHOOK_SECRET!,
  );

  if (event.type === 'payment.completed') {
    const pi = event.data.paymentIntent;
    const { orderId, customerId } = pi.metadata as { orderId: string; customerId: string };
    await db.orders.markPaid(orderId);
    await emailService.sendReceipt(customerId, pi.amount, pi.currency);
  }

  res.sendStatus(200);
});

const intent = await lyel.paymentIntents.retrieve(sessionToken);
if (intent.status === 'EXPIRED') {
  // Create a new intent and restart checkout
  redirect('/checkout');
}

async function resendOtp(userId: string) {
  await lyel.initOtp({ userId, channel: 'sms' });
}

if (event.type === 'payment.failed') {
  await notifyUser('Your payment could not be processed. Please try again.');
}