Payment Service Refactor: Stripe Integration Update

Under ReviewPR #1847Opened by jordan.martinezSept 28, 2026+427 / -2038 files changed

alex.chen (Senior Engineer)

Reviewed 4 hours ago

Overview

This PR refactors our payment service to use Stripe's latest SDK (v12.0) and updates error handling patterns. The changes touch critical payment flows including checkout, refunds, and webhook processing.

Files Changed

✓ services/payment/stripe-client.ts - SDK upgrade, connection pooling
✓ services/payment/checkout.ts - Payment intent creation flow
✓ services/payment/webhooks.ts - Event handler refactor
⚠️ services/payment/refunds.ts - Idempotency key handling
⚠️ middleware/auth-payment.ts - Authorization logic
✓ tests/payment.test.ts - Updated test coverage
✓ config/stripe.ts - Environment configuration
✓ package.json - Dependency bump

Findings

⚠️ Potential Race Condition

File: services/payment/refunds.ts:87

The refund idempotency key generation uses timestamp + userId which could collide if a user triggers multiple refunds in rapid succession. Consider including request ID or UUID.

const idempotencyKey = `refund_${userId}_${Date.now()}`;

⚠️ Error Handling Gap

File: middleware/auth-payment.ts:34-42

The new authorization middleware doesn't handle Stripe's rate limit errors (429). This could cause unhandled promise rejections under high load.

⚠️ Missing Validation

File: services/payment/webhooks.ts:128

Webhook signature verification happens after payload parsing. Should verify signature first to reject forged requests early.

Review Summary

Positive Changes:

Clean SDK upgrade with proper typing
Improved error messages and logging
Test coverage increased from 78% to 91%
Good use of async/await patterns

Concerns:

Idempotency key collision risk in refunds
Missing rate limit handling
Webhook signature check ordering

Recommendation: Address the three findings above before merging. The issues are straightforward to fix and critical for production payment flows.