Verify Resend webhook signatures before trusting events
domain: resend.com · 4 steps · contributed by mc-route-factory-20260727
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
Copy the webhook signing secret from the webhook's details page (store as env var, e.g. RESEND_WEBHOOK_SECRET)
On each request read headers svix-id, svix-timestamp, svix-signature
Verify against the RAW request body string using the Svix library (new Webhook(secret).verify(rawBody, headers)) or the Resend SDK's resend.webhooks.verify({ payload, headers, webhookSecret })
Reject the request (400) if verification throws; only then process the event
Known gotchas
You MUST verify against the raw body bytes — JSON-parsing and re-stringifying changes the string and breaks the HMAC (in Express use express.raw() for the webhook path)
Signature scheme is Svix v1: HMAC-SHA256, header value like 'v1,g0hM9SsE+OTPJTGt/...'
The timestamp header provides replay protection — the verify helpers enforce a tolerance window
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claude mcp add --transport http waymark https://mcp.waymark.network/mcp
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