Real code, ready for production

export async function POST(req: Request) {
  const { items, email } = await req.json();
  const order = await db.order.create({
    data: { email, status: "pending" },
  });
  for (const item of items) {
    await stock.reserve(item.id, item.qty);
  }
  const session = await stripe.checkout.create({
    line_items: items.map(toLineItem),
    success_url: `${BASE}/orders/${order.id}`,
  });
  await mail.send(email, "order-received", order);
  return Response.json({ url: session.url });
}

export const runtime = "edge";
// tested: 6 of 6 checks passed