Payment Gateway Integration

Table of Contents

• Overview
• When to Use
• Quick Start
• Reference Guides
• 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	Stripe Integration with Python/Flask
Node.js/Express Stripe Integration	Node.js/Express Stripe Integration
PayPal Integration	PayPal Integration
Subscription Management	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