Send Google Calendar appointment reminder SMS with RCSZilla

Description

Send free SMS appointment reminders from Google Calendar with n8n and RCSZilla.

This workflow turns Google Calendar into a simple appointment reminder system for opted-in customers. n8n checks tomorrow's events, reads the customer phone number and SMS consent from the calendar event description, prepares a short reminder message, and queues the SMS through RCSZilla.

RCSZilla lets you use your own Android phone and SIM card as the SMS gateway, so you do not need a separate SMS API subscription just to send basic appointment reminders. The workflow is free to run in n8n, and RCSZilla supports device-based sending through your own mobile network. Your mobile carrier plan, country, and message volume can still affect real-world SMS costs, so check your plan before sending production traffic.

Why This Workflow Is Useful

Many appointment-based businesses need a practical SMS reminder service, but do not want to start with a paid SMS provider such as Twilio just to reduce no-shows. This template gives you a direct, phone-based setup:

- Google Calendar stores the appointment. - n8n handles the automation logic. - RCSZilla queues the SMS. - Your connected Android device sends the message through its SIM/mobile plan.

This is a good fit for salons, clinics, dentists, consultants, repair shops, real estate viewings, local agencies, auto service businesses, and other teams that already manage bookings in Google Calendar.