n8n Workflow: Replay-Safe Kickoff Bookings w/ Google Calendar & Gmail

Replay-safe kickoff bookings that confirm with Google Calendar readback and prepare Gmail drafts

This n8n workflow turns kickoff booking requests into confirmed Google Calendar events—only after durable intent is recorded and replays are handled safely. It also prepares customer communication as a Gmail draft (no send), so you can review and control every outgoing message.

What this workflow does

• Authenticates inbound requests by validating a POST webhook using the server-side BOOKING_INTAKE_TOKEN.
• Validates the seven-field booking contract, including real civil dates and agreement on offset/timezone, plus workflow 08 booking-UID derivation.
• Derives deterministic identity evidence for the request (request, parent-scope, intent, and provider identity) to support consistent outcomes.
• Reads stable owner/tag history and checks for replays. If it detects a changed request, it holds it for review before any Calendar operation.
• Persists and acknowledges intent_written, then checks native Google Calendar availability.
• Creates the event, validates the create result, fetches it by ID, and validates the provider readback.
• Persists and acknowledges confirmed, then creates a Gmail draft (attempted without sending) for the customer.
• If reconciliation requires it, the workflow uses a get-only provider lookup—with no create or retry path for unresolved intents.

Use cases

• Automation engineers need idempotent scheduling for kickoff calls to prevent duplicate events.
• SaaS operators want confirmed bookings with Calendar readback validation and draft-only customer messaging.
• Teams handling multi-step intake want changed requests held for review instead of blindly rescheduling.

Technical details

• n8n nodes: webhook, if, switch, code, data table, gmail.
• Data persistence: create a Bookings Data Table with mapped insert/update columns, then re-select it in every Data Table node.
• Environment variables: BOOKING_INTAKE_TOKEN and BOOKING_CALENDAR_ID.
• Google Calendar: availability, event create, created-event get by ID, and reconciliation get.
• Gmail: Create Confirmation Draft (draft creation only; no sending).