Webhook Signature Verifier
Verify webhook HMAC signatures to prove payloads came from the provider untampered. Reject forged events before processing — local crypto, free, no signup.
How to Use the Webhook Signature Verifier
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Frequently Asked Questions
How does verification work?
Recompute HMAC over the raw body with your shared secret and compare to the signature header using constant-time equality. Match means authentic and untampered.
Why did verification fail?
Usual suspects: parsed-then-reserialized body (whitespace changed), wrong secret (test vs live), or timestamp outside tolerance. Always verify the RAW body bytes.
Which algorithms?
HMAC-SHA256 dominates (Stripe, GitHub); some use SHA1 or Ed25519. Match the provider's documented scheme exactly — close doesn't verify.
Are secrets uploaded?
No — crypto runs locally in your browser via Web Crypto. Secrets never leave your device.
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Last updated October 2026