Building a Food Delivery Marketplace on Paystack

// Create a Transaction Split group for an order
async function createOrderSplit(restaurantSubaccount, riderSubaccount, orderTotal, deliveryFee) {
  var restaurantAmount = orderTotal - deliveryFee;
  var platformCommissionRate = 0.08; // 8%
  var restaurantShare = restaurantAmount * (1 - platformCommissionRate);

  var response = await fetch('https://api.paystack.co/split', {
    method: 'POST',
    headers: { Authorization: 'Bearer ' + process.env.PAYSTACK_SECRET_KEY, 'Content-Type': 'application/json' },
    body: JSON.stringify({
      name: 'Order split',
      type: 'flat', // flat kobo amounts
      currency: 'NGN',
      subaccounts: [
        { subaccount: restaurantSubaccount, share: Math.round(restaurantShare * 100) },
        { subaccount: riderSubaccount, share: Math.round(deliveryFee * 100) },
      ],
      bearer_type: 'account',
    }),
  });
  var data = await response.json();
  return data.data.split_code; // e.g., SPL_xxxxxx
}

// Initialize order payment with the split
app.post('/api/orders', async (req, res) => {
  var { restaurantId, riderId, items, email } = req.body;

  var restaurant = await db.restaurants.findById(restaurantId);
  var rider = await db.riders.findById(riderId);
  var orderTotal = items.reduce((s, i) => s + i.price * i.qty, 0);
  var deliveryFee = 500; // NGN 500

  var splitCode = await createOrderSplit(
    restaurant.subaccount_code,
    rider.subaccount_code,
    orderTotal,
    deliveryFee
  );

  var response = await fetch('https://api.paystack.co/transaction/initialize', {
    method: 'POST',
    headers: { Authorization: 'Bearer ' + process.env.PAYSTACK_SECRET_KEY, 'Content-Type': 'application/json' },
    body: JSON.stringify({
      email,
      amount: Math.round((orderTotal + deliveryFee) * 100),
      split_code: splitCode,
      metadata: { order_id: 'ord_' + Date.now(), restaurant_id: restaurantId },
    }),
  });

  var data = await response.json();
  res.json({ authorization_url: data.data.authorization_url });
});

if (event.event === 'charge.success') {
  var orderId = event.data.metadata?.order_id;
  if (!orderId) return;

  await db.orders.update({ status: 'paid', paid_at: new Date() }, { where: { reference: event.data.reference } });

  // Notify restaurant to start preparing
  await notifyRestaurant(orderId);
  // Notify rider to go pick up
  await notifyRider(orderId);
}

This guide is part of the Paystack split payments guide.

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