Agent skill

payment-gateway-integration

Integrates payment processing with Stripe, PayPal, or Square including subscriptions, webhooks, and PCI compliance. Use when implementing checkout flows, recurring billing, or handling refunds and disputes.

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Forks 31

Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/payment-gateway-integration

SKILL.md

Payment Gateway Integration

Integrate secure payment processing with proper error handling and compliance.

Stripe Integration (Node.js)

javascript
const stripe = require('stripe')(process.env.STRIPE_SECRET_KEY);

class PaymentService {
  async createPaymentIntent(amount, currency, customerId) {
    return stripe.paymentIntents.create({
      amount: Math.round(amount * 100), // Convert to cents
      currency,
      customer: customerId,
      automatic_payment_methods: { enabled: true }
    });
  }

  async createSubscription(customerId, priceId) {
    return stripe.subscriptions.create({
      customer: customerId,
      items: [{ price: priceId }],
      payment_behavior: 'default_incomplete',
      expand: ['latest_invoice.payment_intent']
    });
  }

  async refund(paymentIntentId, amount = null) {
    const params = { payment_intent: paymentIntentId };
    if (amount) params.amount = Math.round(amount * 100);
    return stripe.refunds.create(params);
  }
}

Webhook Handling

javascript
app.post('/webhooks/stripe', express.raw({ type: 'application/json' }), (req, res) => {
  const sig = req.headers['stripe-signature'];

  let event;
  try {
    event = stripe.webhooks.constructEvent(req.body, sig, process.env.STRIPE_WEBHOOK_SECRET);
  } catch (err) {
    return res.status(400).send(`Webhook Error: ${err.message}`);
  }

  switch (event.type) {
    case 'payment_intent.succeeded':
      await handlePaymentSuccess(event.data.object);
      break;
    case 'invoice.payment_failed':
      await handlePaymentFailed(event.data.object);
      break;
  }

  res.json({ received: true });
});

PayPal Integration

See references/paypal-integration.md for complete PayPal implementation with:

  • Order creation and capture
  • Refund processing
  • Webhook handling
  • Frontend SDK integration
  • Success/cancel callbacks

Security Checklist

  • Use official SDK only
  • Verify webhook signatures
  • Never log full card numbers
  • Store minimal payment data
  • Test in sandbox first
  • HTTPS for all payment routes
  • Handle all error cases
  • Use idempotency keys
  • Implement retry logic

Best Practices

Do:

  • Use official SDK libraries
  • Verify all webhook signatures
  • Log transaction IDs (not card data)
  • Test in sandbox environment
  • Handle all payment states
  • Implement proper error messages

Don't:

  • Process raw card data directly
  • Store sensitive payment info
  • Hardcode API keys
  • Skip webhook signature validation
  • Ignore failed payment events
  • Use test keys in production

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