1. Why Webhooks Represent the Most Vulnerable Ingestion Point in Commerce
Because client redirects can be closed or manipulated, webhook callbacks are the definitive source of payment truth. However, unsecured endpoints allow attackers to spoof payment confirmations or cause duplicate fulfillments.
2. Cryptographic HMAC-SHA256 Signature Verification
HMAC verification and timing-safe equality checks ensure malicious payloads cannot spoof successful settlements or bypass cryptographic authenticity gates.
3. Idempotency Keys: Eliminating Duplicate Billing and Fulfillments
Atomic Redis idempotency guards intercept duplicate network retries, returning cached success acknowledgments without executing duplicate fulfillment jobs.