payment-gateway-integration

# 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; ...