agent-11: Skill for Claude Code

SaaS Payments & Stripe Integration

Capability

Implement production-ready payment processing with Stripe including one-time payments, recurring subscriptions, customer portal, metered billing, and webhook handling. This skill covers the complete billing lifecycle from checkout through subscription management.

Use Cases

• One-time product purchases with Checkout
• Subscription plans with monthly/yearly billing
• Customer self-service portal for billing management
• Usage-based/metered billing for API products
• Invoice generation and payment tracking
• Handling failed payments and dunning
• Upgrading/downgrading subscription plans

Patterns

Stripe Checkout for One-Time Payments

When to use: Single purchases, credits, one-time fees

Implementation: Create Checkout session server-side, redirect customer to Stripe-hosted page.

// Create checkout session for one-time payment
async function createCheckoutSession(userId: string, priceId: string, quantity = 1) {
  // Get or create Stripe customer
  const customer = await getOrCreateStripeCustomer(userId);

  const session = await stripe.checkout.sessions.create({
    customer: customer.id,
    mode: 'payment',
    line_items: [
      {
        price: priceId, // price_xxx from Stripe Dashboard
        quantity,
      },
    ],
    success_url: `${process.env.APP_URL}/checkout/success?session_id={CHECKOUT_SESSION_ID}`,
    cancel_url: `${process.env.APP_URL}/checkout/cancel`,
    metadata: {
      userId, // Store for webhook processing
    },
    // Enable invoice for one-time payments
    invoice_creation: {
      enabled: true,
    },
  });

  return { url: session.url };
}

// Get or create Stripe customer linked to user
async function getOrCreateStripeCustomer(userId: string) {
  const user = await db.user.findUnique({ where: { id: userId } });

  if (user.stripeCustomerId) {
    return await stripe.customers.retrieve(user.stripeCustomerId);
  }

  const customer = await stripe.customers.create({
    email: user.email,
    name: user.name,
    metadata: {
      userId,
    },
  });

  await db.user.update({
    where: { id: userId },
    data: { stripeCustomerId: customer.id },
  });

  return customer;
}