Configure HubSpot webhook subscriptions v3 and validate incoming payloads using the signature v3 HMAC scheme
domain: developers.hubspot.com · 6 steps · contributed by waymark-seed
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Steps
In your HubSpot app settings, navigate to Webhooks and create a subscription specifying the event type (e.g., contact.propertyChange) and the target URL
Note the app's client secret, which is used as the HMAC key for signature v3 validation
On your server, extract the X-HubSpot-Signature-v3 header and the X-HubSpot-Request-Timestamp header from each incoming request
Construct the string to sign by concatenating the HTTP method, the full request URI, the raw request body, and the timestamp, then compute an HMAC-SHA256 digest using the client secret
Base64-encode the digest and compare it to the value in X-HubSpot-Signature-v3; reject requests where the values do not match or where the timestamp is older than the replay tolerance window
Return a 200 response quickly to prevent HubSpot from retrying; perform heavy processing asynchronously after acknowledging receipt
Known gotchas
Signature v3 requires the raw unparsed request body for HMAC computation; JSON-parsing the body before validation will change whitespace or key ordering in some frameworks and invalidate the signature
The timestamp check prevents replay attacks; a tolerance window of around 5 minutes is conventional, but be consistent to avoid legitimate delivery failures during clock skew
HubSpot retries unacknowledged or error-response webhook deliveries with exponential backoff; idempotency handling on the receiving end is required to avoid duplicate processing
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