n8n Referral Webhook → Google Sheets Ledger + Thank-You Email

Turn referral form submissions into a tracked ledger, compliant thank-yous, and monthly reminders—fully automated

This n8n workflow receives referral submissions via a webhook, appends them to a Google Sheets “Referrals” ledger, sends plain-text thank-you emails through a compliance/opt-out guardrail sub-workflow (when a referrer email exists), notifies your firm, and then runs monthly to generate a reciprocal-referral reminder digest based on the last 90 days.

What this workflow does

• Receives referral submissions via a webhook endpoint.
• Normalizes and validates payload data, ensuring required referrer details exist before recording anything.
• Appends valid referrals to Google Sheets (the “Referrals” tab) including date, lead details, and referrer metadata (name, email, type, matter type, and status).
• Sends compliant thank-you emails to referrers only when a referrer email is present:
  • Generates a plain-text thank-you message.
  • Routes it through a guardrail sub-workflow (for compliance/opt-out handling) before delivery via SMTP.
• Emails your firm a referral summary via SMTP regardless of whether the thank-you was sent, skipped, or suppressed.
• Runs on the 1st of every month: reads the full ledger, calculates per-referrer referral counts for the last 90 days, filters referrers that meet the repeat threshold, and sends your firm a digest reminder email (also logged via the guardrail workflow).

Use cases

• A law firm capturing partner referrals through a web form and keeping a referral ledger in Google Sheets.
• Automation engineers standardizing referral tracking while maintaining email compliance and opt-out guardrails.
• SaaS operators needing monthly “reciprocal referral” outreach based on repeat activity.

Technical details

• n8n nodes / logic: webhook, code, if, filter, aggregate, no op.
• Integrations: Google Sheets (OAuth2) and SMTP (email delivery).
• Compliance: guardrail sub-workflow used before sending thank-you/reminder communications.