Detect Revenue Leakage: n8n Audit Sheets, Gemini & Gmail

Stop Revenue Leakage with Automated n8n Audits (Sheets + Gemini + Gmail)

This n8n workflow audits your invoices, delivered work, payments, and follow-ups in Google Sheets to detect revenue leakage—then generates recovery next-steps with Google Gemini and sends customer emails via Gmail or posts internal alerts to Slack.

What this workflow does

• Runs on a schedule and loads configuration values like your Google Sheets spreadsheet ID and aging thresholds.
• Reads Google Sheets tabs: Invoices, Work Delivered, Payments, and Follow-ups.
• Correlates records to spot issues such as unbilled work, duplicate billing, billing variance, draft invoices not sent, balance mismatches, orphan payments, and overdue/due-soon invoices with insufficient follow-up.
• Creates prioritized recovery tasks (with next-action dates) and appends them to the Follow-ups sheet, limited to the first two findings per run.
• Drafts messages with Google Gemini: for each finding, it builds a prompt and generates a JSON draft containing subject, body, and a recommended action.
• Notifies via Gmail or Slack: if the finding is customer-facing and an email address exists, it emails the customer using Gmail; otherwise it posts an internal alert to the selected Slack channel.
• Produces an audit summary including total findings processed and total amount at risk.

Use cases

• Catch unbilled delivered work before it turns into lost cash.
• Identify orphan payments or balance mismatches and launch recovery outreach.
• Ensure draft invoices are actually sent and follow-ups happen on time.

Technical details

• Integrations/inputs: Google Sheets (Invoices, Work Delivered, Payments, Follow-up)
• LLM: Google Gemini (JSON message drafts: subject/body/recommended action)
• Messaging: Gmail for customer emails; Slack for internal alerts
• Workflow logic nodes: if, set, code, gmail, limit, slack

Setup requirement

Create a Google Sheets file with tabs named exactly: Invoices, Work Delivered, Payments, and Follow-up.