n8n Workflow: Tiered Google Sheets Appointment Reminders via Gmail

Send Tiered Google Sheets Appointment Reminders via Gmail—Automated Every Morning

This n8n workflow automatically checks upcoming appointments in your Google Sheets and sends tiered appointment reminders through Gmail—then updates the reminder status back in the sheet and emails staff with a daily delivery summary.

What this workflow does

• Runs every morning on a schedule and validates required configuration (Google Sheet ID, email addresses, booking URL, and reminder-day offsets).
• Reads the Google Sheets “Bookings” tab (including formatted values) and stops if required column headers are missing or incorrectly typed.
• Selects confirmed, future bookings that fall into the next reminder window (default: 7, 3, and 1 days before the appointment).
• Prevents duplicates and skips invalid rows by validating booking IDs, dates/times, and email addresses.
• Sends Gmail reminders for each due booking, routing messages based on mode: staff address in test mode, client address in live mode.
• Uses special confirmation messaging for higher no-show risk clients, asking those clients to reply to confirm.
• Updates Google Sheets before/after sending: marks reminders as “sending,” sends via Gmail, then writes back success—or reverts on failure so it can retry next run.
• Emails staff daily summaries whenever reminders go out, including:
  • delivered vs. failed reminder results
  • who was asked to confirm
  • a separate list of rows skipped due to invalid identifiers, dates/times, or email addresses

Use cases

• Reducing missed appointments by sending automated reminders at 7/3/1 days.
• Lowering no-show rates by prompting higher-risk clients to reply to confirm.
• Operational visibility: staff receive a daily Gmail delivery and data-quality report.

Technical details

• n8n scheduling + validation via Set and Code nodes
• Google Sheets integration using an HTTP Request approach to read formatted booking data
• Gmail delivery with routed recipients for test/live modes
• Error handling using an Error Trigger node
• Includes a Sticky Note for workflow guidance