n8n Workflow: Google Calendar SMS Appointment Reminders

Never miss an appointment—this n8n workflow sends Google Calendar SMS reminders automatically

This n8n workflow checks your upcoming Google Calendar events every hour, extracts the client’s name and mobile number from the event details, and sends a personalized SMS appointment reminder via the SMS Vert Pro MCP API. It also writes a sent/failed marker back into the event description to prevent duplicate reminders.

What this workflow does

• Runs on a schedule (hourly) to process upcoming appointments.
• Fetches events from now through the next configured hours (default: 24) and expands recurring events.
• Skips events that are cancelled or all-day, and ignores events already tagged with an SMS reminder marker.
• Enforces sending hours, so reminders only go out at appropriate times.
• Extracts client name and a mobile number from the event description/location, then generates a personalized SMS message from a template.
• If a valid mobile number is found, sends the SMS using the SMS Vert Pro MCP endpoint and records whether it succeeded or failed.
• Updates the Google Calendar event description with:
  • [SMS reminder sent …] when successful
  • [SMS reminder failed …] when sending fails
  • [SMS reminder not sent: no mobile number found] when the number is missing (so it can be fixed and retried)

Use cases

• Reduce no-shows for client appointments by sending reminders based on your existing Google Calendar entries.
• Operational troubleshooting: quickly identify which events failed SMS delivery and why (marker written back to the event).
• Mobile number validation workflow: automatically flag events missing a phone number.

Technical details

• Nodes / stack: if, set, code, sticky note, Google Calendar, Schedule Trigger
• Integrations: Google Calendar + SMS Vert Pro MCP API (Bearer Auth using your SMS Vert Pro API V2 token)
• Core logic: scheduled event reading, recurring expansion, SMS sending, and event description status updates to prevent duplicates