TL;DR
- webhook hmac signature verification 2026
- For backends receiving webhooks from payments, CI, and partners.
Who this is for
- For backends receiving webhooks from payments, CI, and partners.
Keyword (SEO)
webhook hmac signature verification 2026
Algorithm
- Read raw body before JSON parse—otherwise signatures never match.
- HMAC-SHA256(secret, payload) or vendor scheme.
- Constant-time compare (crypto.timingSafeEqual).
Replay
- Vendor timestamp header + e.g. 5 minute window.
- Store event_id with TTL to drop duplicates.
Common mistakes
- Read raw body before JSON parse—otherwise signatures never match.
- HMAC-SHA256(secret, payload) or vendor scheme.
FAQ
401 vs 400 on bad signature?
Often 400/401 without details—avoid leaking validation hints.