n8n Workflow: Google Sheets to Calendar Appointments + Gmail Reminders

Turn new Google Form appointment requests into confirmed Google Calendar events—with Gmail reminders

This n8n workflow watches your Google Sheets form responses for new patient booking requests, verifies availability in Google Calendar, creates confirmed appointments, and sends both confirmation and timed reminder emails via Gmail—while saving the booking record in Supabase.

What this workflow does

• Hourly trigger: Runs every hour when a new row is added to your Google Sheets form responses sheet.
• Normalize and schedule: Processes submitted patient details, combines the preferred date and time into an ISO appointment start datetime.
• Check availability: Looks at the doctor’s Google Calendar for existing events in the requested 30-minute time window.
• Handle unavailable slots: If the slot is taken, sends an “Appointment Slot Unavailable” email using Gmail.
• Confirm available appointments: If available, creates the appointment event in Google Calendar and captures the calendar event ID.
• Persist booking data: Saves patient, doctor, time, symptoms, event ID, and status to a Supabase table.
• Send reminders: Uses a wait step to send a reminder email via Gmail two hours before the appointment time, then updates the Supabase record status to “Reminder Sent.”

Use cases

• Clinics that collect appointments via Google Forms into a Google Sheets response sheet.
• Teams that need real-time-ish scheduling without manual calendar checks or copy/paste email sending.
• SaaS operators and automation engineers building an n8n-backed booking pipeline with audit-ready storage in Supabase.

Technical details

• Triggers & logic: hour-based trigger, if, set, and wait steps
• Integrations: Google Sheets, Google Calendar, Gmail, Supabase
• Additional node: sticky note for workflow clarity

Setup: Connect Google Sheets (select spreadsheet/sheet), Google Calendar (choose calendar), Gmail (configure templates for unavailable/confirmation/reminder), and Supabase (connect your database).