n8n Google Sheets to Gmail: Send Post-Visit Review Requests

Automatically email Google review requests to customers after their visit—then let them unsubscribe with one click

This n8n workflow reads completed visits from your Google Sheets, waits a configurable delay, and sends customers an HTML Gmail/SMTP email containing your Google review link. It also provides a personalized unsubscribe link via an n8n webhook and records when each request was sent.

What this workflow does

• Runs hourly on a schedule.
• Reads visit records from the “Visits” tab in Google Sheets.
• Filters eligible customers by checking: completed status, a valid email, a configurable “ended at least X hours ago” rule, a configurable max age, not previously asked (based on review_requested_at), not opted out (based on opt_out), and quiet hours.
• Sends the review request email using Email Send (SMTP), including:
  • Your Google review link
  • A one-click unsubscribe link that points to the workflow’s webhook
• Updates the matching Google Sheets row by setting review_requested_at when the email is successfully sent.
• Serves an opt-out webhook that validates the visit and email from the unsubscribe link, marks opt_out as TRUE for that email in Google Sheets, and returns an unsubscribe confirmation page.

Use cases

• Increase review volume for a service business by requesting reviews after completed appointments.
• Run a compliant, trackable request process that avoids re-contacting opted-out customers.
• Reduce manual follow-up by letting n8n handle timing, quiet hours, and delivery tracking.

Technical details

• Google Sheets integration (reads from and updates the Visits tab)
• Email Send (SMTP/Email) to send HTML review request messages
• Webhook for unsubscribe handling
• Nodes mentioned: if, set, code, webhook, email send, sticky note

Works best when your sheet includes columns: visit_id, client_name, email, visit_end, timezone, status, review_requested_at, opt_out, with status set to completed for eligible visits.