Notion Webhooks When to Use This Skill - Setting up Notion webhook handlers for an internal integration - Debugging Notion signature verification failures - Completing the one-time handshake to activate a subscription - Handling page, comment, database, or data source events from a Notion workspace Essential Code (USE THIS) Notion uses HMAC-SHA256 over the raw request body with the integration's as the signing key. The signature is sent in the header in the format . The first POST to a new subscription is a handshake : it contains a in the JSON body and has no signature . The handler must cap…