Payment Gateway Integration Security Testing — 日本企業向けガイド

Payment gateway integrations — Stripe, PayPal, Adyen, local payment processors — are critical security boundaries where money changes hands. Testing covers: webhook verification (are payment notifications authenticated and validated?), transaction amount integrity (can the amount be manipulated between your application and the gateway?), idempotency (are duplicate payment requests handled safely?), refund flow security, and error handling (do payment failures expose sensitive information or create exploitable states?).