/payment-gateway-integration

name: payment-gateway-integration
description: >
  Integrate payment gateways like Stripe, PayPal, and Square with backends for
  payment processing, subscription management, and webhook handling. Use when
  building e-commerce platforms, implementing billing systems, and handling
  payments securely.

Payment Gateway Integration

Table of Contents

• [Overview](#overview)
• [When to Use](#when-to-use)
• [Quick Start](#quick-start)
• [Reference Guides](#reference-guides)
• [Best Practices](#best-practices)

Overview

Build secure payment processing systems with major payment providers (Stripe, PayPal, Square), handling transactions, subscriptions, webhooks, PCI compliance, and error scenarios across different backend frameworks.

When to Use

• Processing customer payments
• Implementing subscription billing
• Building e-commerce platforms
• Handling refunds and disputes
• Managing recurring charges
• Integrating payment webhooks

Quick Start

Minimal working example:

# config.py
import os

class StripeConfig:
    STRIPE_SECRET_KEY = os.getenv('STRIPE_SECRET_KEY')
    STRIPE_PUBLISHABLE_KEY = os.getenv('STRIPE_PUBLISHABLE_KEY')
    STRIPE_WEBHOOK_SECRET = os.getenv('STRIPE_WEBHOOK_SECRET')

# stripe_service.py
import stripe
from datetime import datetime, timedelta
import logging

logger = logging.getLogger(__name__)

stripe.api_key = os.getenv('STRIPE_SECRET_KEY')

class StripePaymentService:
    @staticmethod
    def create_payment_intent(amount, currency='usd', description=None, metadata=None):
        """Create a payment intent"""
        try:
            intent = stripe.PaymentIntent.create(
                amount=int(amount * 100),  # Convert to cents
                currency=currency,
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the `references/` directory:

| Guide | Contents | |---|---| | [Stripe Integration with Python/Flask](references/stripe-integration-with-pythonflask.md) | Stripe Integration with Python/Flask | | [Node.js/Express Stripe Integration](references/nodejsexpress-stripe-integration.md) | Node.js/Express Stripe Integration | | [PayPal Integration](references/paypal-integration.md) | PayPal Integration | | [Subscription Management](references/subscription-management.md) | Subscription Management |

Best Practices

✅ DO

• Use official payment SDK libraries
• Verify webhook signatures
• Store minimal payment information
• Never store full credit card numbers
• Use HTTPS for all payment routes
• Implement proper error handling
• Test with sandbox environments
• Handle payment failures gracefully
• Implement PCI compliance
• Log all payment transactions
• Use idempotency keys
• Implement retry logic

❌ DON'T

• Handle raw card data
• Store sensitive payment information
• Log sensitive details
• Trust client-side validation only
• Ignore webhook events
• Hardcode API keys
• Use test keys in production
• Skip SSL/TLS verification
• Forget to validate amounts
• Store payment tokens without encryption