Payment System Launch Security Checklist

TL;DR

Before accepting real payments, use a PCI-compliant payment processor (Stripe, Paddle), never handle raw card numbers, verify webhook security, test the complete payment flow, enable fraud detection, and make sure your secret keys are never exposed.

Payment Processing 4

Use a PCI-compliant processorStripe, Paddle, PayPal, or similar. Never handle raw card numbers yourself.

Use hosted payment formsStripe Checkout, Elements, or similar. Card data never touches your server.

Switch to live/production modeReplace test API keys with production keys

Test complete payment flowMake a small real purchase to verify everything works

API and Webhook Security 4

Secret keys are server-side onlyNever expose payment API secrets in browser or client code

Verify webhook signaturesAlways validate that webhooks came from your payment provider

Make webhook handlers idempotentWebhooks can be sent multiple times. Handle duplicates gracefully.

Use HTTPS everywhereAll payment-related pages and APIs must use HTTPS

Fraud Prevention 4

Enable fraud detectionUse Stripe Radar, PayPal fraud protection, or similar

Add rate limiting to payment endpointsPrevent card testing attacks by limiting attempts

Require authentication for purchasesLogged-in users reduce fraud and simplify disputes

Monitor for unusual patternsSet up alerts for high volumes or unusual activity

Business and Legal 4

Display clear pricingShow total including taxes before checkout

Have refund policy visibleRequired by most payment processors and builds trust

Send receipts for purchasesEmail confirmation for every successful payment

Log payment eventsKeep records for disputes, refunds, and accounting

Do I need PCI compliance?

If you use a payment processor like Stripe or PayPal and never handle raw card numbers, they handle PCI compliance. If card data ever touches your servers, you have significant compliance requirements.

How do I prevent card testing fraud?

Enable rate limiting on payment endpoints, require user authentication, enable your payment processor's fraud detection (like Stripe Radar), and monitor for patterns like many small charges.

Scan Your Payment Integration

Find exposed keys and security issues before launch.