n8n Appointment No-Show + Waitlist Refill Automation (Twilio, Gmail, OpenAI)

Fill appointment no-shows automatically—Google Calendar + Twilio/Gmail + waitlist powered by OpenAI

This n8n workflow monitors your upcoming Google Calendar appointments, detects no-show risk, offers freed slots from your waitlist, and sends confirmations/recalls via Twilio SMS or Gmail. It also reads incoming replies, uses OpenAI to classify intent, and updates both your Google Sheets log and Google Calendar bookings accordingly.

What this workflow does

• Runs on a schedule and reacts instantly: executes every 15 minutes, and also handles inbound replies received via Twilio (SMS) or Gmail (email).
• Loads operational data from Google Sheets: reads the Clients, Services, Waitlist, and Log tabs to track history and availability.
• Plans next actions based on calendar state: logs confirmation messages (including a 48-hour ask and a 24-hour nudge), prepares batch waitlist offers for freed slots, and generates recall messages plus daily/weekly staff reports.
• Sends messages with channel + opt-out handling: appends planned actions to the Sheets Log first, then delivers outbound confirmations, waitlist offers, and recall messages via Twilio SMS or Gmail depending on recipient settings.
• Understands replies and updates bookings: normalizes inbound SMS/email, filters out unknown senders and automatic/out-of-office messages, then uses OpenAI to extract reply intent with quoted evidence.
• Applies outcomes to the right message: updates the Log and creates or deletes Google Calendar events when cancellations occur or a waitlist slot is accepted, including front desk email notifications when a reply requires attention.

Use cases

• Reduce revenue loss from appointment no-shows by moving waitlist candidates into confirmed slots.
• Send timed confirmation + recall sequences while maintaining an auditable history in Google Sheets.
• Automate staff reporting based on calendar state and prior log history.

Technical details

• Google Sheets: Clients, Services, Waitlist, and Log storage + action auditing
• Google Calendar: reads upcoming events, creates/deletes events for accepted waitlist slots and cancellations
• Twilio: inbound SMS replies + outbound SMS messaging
• Gmail: outbound email and inbound reply handling
• OpenAI: classifies incoming reply intent using extracted evidence
• n8n nodes/tools: set, code, gmail, switch, twilio, aggregate