Skip the Tutorials.
Code in Production.

export async function POST(req: Request) {
  const body = await req.json();
  const signature = req.headers.get("stripe-signature");

  // Verify webhook signature authenticity
  const event = stripe.webhooks.constructEvent(
    body, signature, process.env.STRIPE_WEBHOOK_SECRET
  );

  if (event.type === "checkout.session.completed") {
    await db.user.update({
      where: { id: event.data.object.metadata.userId },
      data: { subscriptionStatus: "ACTIVE" }
    });
  }
  return Response.json({ received: true });
}