Payment Integration Security Checklist: 15-Item Guide Before Adding Stripe

TL;DR

Payment security is non-negotiable. Use Stripe Elements or Checkout so you never handle raw card data. 6 critical items must be verified before processing any payments, 5 important items should be done within the first week, and 4 recommended items as you scale. Verify webhook signatures, use test mode first, keep secret keys server-side only, and monitor for fraudulent activity. Follow this checklist before processing any real payments.

Quick Checklist (5 Critical Items)

Use Stripe Elements, Checkout, or Payment LinksNever accept card numbers directly in your code

Secret key only on serversk_live_ and sk_test_ keys must never be in frontend

Store keys in environment variablesNever commit Stripe keys to your repository

Verify webhook signaturesUse Stripe's signature verification, never trust unverified webhooks

Test all flows in test mode firstUse test card numbers before going live

Never Touch Card Data 3

Use Stripe Elements, Checkout, or Payment LinksNever accept card numbers directly. Let Stripe handle sensitive data. How to set up Stripe Elements

Verify no card numbers in your codebaseSearch for patterns like 4[0-9]{15} or card_number. Should find nothing. How to scan for card data

Verify no card data in logsCheck application logs for any accidentally logged payment info. How to secure payment logs

API Keys and Secrets 4

Secret key only on serversk_live_ and sk_test_ keys must never appear in frontend code. How to secure Stripe keys

Use publishable key for frontendpk_live_ and pk_test_ keys are safe for browser. Understanding Stripe key types

Store keys in environment variablesNever commit Stripe keys to your repository. How to secure API keys

Use separate keys for test and productionDifferent environments should use different API keys. How to use Stripe test mode

Webhook Security 4

Verify webhook signaturesUse Stripe's signature verification. Never trust unverified webhooks. How to verify Stripe webhooks

Use HTTPS for webhook endpointWebhook URLs must use HTTPS, not HTTP. How to set up HTTPS

Handle all relevant eventsProcess payment_intent.succeeded, checkout.session.completed, etc. How to handle Stripe webhook events

Make webhooks idempotentProcessing the same event twice should not cause problems. How to make webhooks idempotent

Testing and Fraud Prevention 4

Test all flows in test mode firstUse test card numbers (4242 4242 4242 4242) before going live. How to use Stripe test mode

Enable Stripe Radar for fraud detectionUse Stripe's built-in fraud prevention tools. How to set up Stripe Radar

Add rate limiting to checkoutPrevent card testing attacks by limiting payment attempts. How to rate limit checkout

Monitor for unusual activitySet up alerts for high volumes, failed payments, or unusual patterns. How to monitor payment activity

Why Payment Security is Different

Payment security has higher stakes than general application security. A breach can result in financial losses, chargebacks, loss of payment processing ability, and potentially PCI compliance violations with significant fines.

The good news: modern payment processors like Stripe handle most of the hard work. By using Stripe Elements or Checkout, card data never touches your servers, dramatically reducing your PCI compliance scope and risk.

Do I need to be PCI compliant?

If you use Stripe Elements, Checkout, or similar tools where card data never touches your servers, you can self-certify with PCI SAQ-A, the simplest compliance level. If you handle card data directly (which you should not), you need full PCI compliance.

What if my Stripe secret key is exposed?

Immediately roll the key in Stripe Dashboard. An attacker with your secret key can issue refunds, create charges, and access customer data. After rolling, update your environment variables and audit recent activity for unauthorized actions.

How do I handle refunds securely?

Refunds should only be triggered by authenticated admin users or verified webhook events. Never allow customers to trigger refunds directly. Log all refund actions for audit purposes.

TL;DR

Quick Checklist (5 Critical Items)

Never Touch Card Data 3

API Keys and Secrets 4

Webhook Security 4

Testing and Fraud Prevention 4

Why Payment Security is Different

Do I need to be PCI compliant?

What if my Stripe secret key is exposed?

How do I handle refunds securely?

Related Articles

Webhook Security Checklist

Cost of Payment Fraud

Environment Variables Guide

Payment-Ready Security Scan

Payment Integration Security Checklist: 15-Item Guide Before Adding Stripe