stripe integration reviewer

The problem

Stripe integration code often fails silently in production due to redelivered webhooks, out-of-order events, and unhandled disputes. Developers frequently assume a try/catch block ensures idempotency, but without a dedicated claim-and-complete mechanism, you risk double-charging customers or losing data during crashes.

What it does

• Audits webhook handlers for strict signature verification using raw request bytes to prevent downgrade attacks.
• Identifies race conditions caused by Stripe's at-least-once, out-of-order event delivery guarantees.
• Verifies that idempotency logic uses an atomic claim-then-complete pattern keyed on event IDs.
• Checks for coverage of critical dispute and chargeback lifecycle events within your application logic.
• Generates integration tests utilizing Stripe Test Clocks to simulate subscription transitions like trial expiry and dunning.

Frameworks & tools

Works with Node.js (Express, Next.js Pages/App Router), Python (Flask, Django), and any stack using the official Stripe SDK. Specifically identifies framework-specific pitfalls like middleware body-parsing that breaks signature verification.

Why this beats prompting it yourself

General LLMs often suggest simple "insert-if-not-exists" patterns that still leave windows for data loss if a process crashes mid-execution. This skill enforces a specific two-step atomic protocol and monotonicity checks for state updates, ensuring your integration handles the edge cases documented in Stripe's technical snapshots.

Use cases

• Auditing a new payment flow before it handles real production transactions.
• Debugging "double-grant" or "double-charge" bugs caused by webhook redelivery.
• Adding programmatic handling for disputes and chargebacks to automate account flagging.
• Building a test suite that actually triggers time-dependent subscription events.

Known limitations

Does not cover PCI-DSS compliance or client-side script integrity. Limited to Stripe integrations, as logic does not transfer to other payment providers. Does not execute live API calls.