Guide
Webhook Signature Verification: Practical Checklist
Webhook security is about predictable verification, replay protection, and consistent logging. A simple checklist prevents most integration mistakes.
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Verification steps
Read the raw request body before JSON parsing side effects.
Compute HMAC with your signing secret and compare using constant-time checks.
Reject requests outside your accepted timestamp window.
Replay and idempotency
Store webhook id or submission id to prevent duplicate processing.
Treat retries as normal behavior and make handlers idempotent by default.
Return 2xx only after your minimal acceptance path succeeds.
Operations checklist
Rotate secrets with a planned deployment sequence.
Alert on signature failures and sudden validation spikes.
Document receiver behavior so on-call engineers can triage quickly.
Frequently asked questions
Can I skip signature verification in early testing?
You can, but production endpoints should always verify signatures and timestamps.
Do retries mean something is broken?
Not necessarily. Retries are expected on transient failures and should be safely handled.
Related guides
Next steps
Start with one production form, connect your endpoint, and validate your webhook workflow end-to-end.
- Create your endpoint URL on formsig.com and submit once from your real page.
- Set webhook + anti-spam controls before scaling traffic.
- Use playground demos for quick team handoff and QA.