Monitor Refund & Chargeback Spikes | Sheets, Gemini, Slack

Spot refund & chargeback spikes before they hurt your revenue—automatically

This n8n workflow monitors Google Sheets daily for refund and chargeback spikes, compares a rolling 7-day ratio to a 90-day baseline, and immediately posts a Slack alert with a Google Gemini diagnostic summary when an anomaly is detected.

What this workflow does

• Runs daily at 09:00 based on your n8n instance timezone.
• Loads configuration such as the anomaly threshold multiplier, optional monitoring date override, Google Sheets IDs/tab names, and the Slack channel.
• Reads sales data and refund/chargeback data from two Google Sheets tabs (e.g., “Sales” and “Refunds”).
• Calculates ratios: computes the current 7-day refund/chargeback ratio and compares it to a 90-day historical baseline.
• Flags anomalies when the current ratio exceeds the baseline by the configured multiplier; if there’s insufficient data, it assigns an appropriate status.
• When a spike is detected, uses Google Gemini to generate a concise diagnostic summary, then:
  • Logs metrics + summary to a Google Sheets log tab
  • Sends a Slack alert with the key metrics and Gemini text
• When no anomaly occurs, it still logs metrics and status to the Google Sheets log tab, but does not alert Slack.

Use cases

• Detect sudden increases in refunds/chargebacks after a promo, product update, or payment method change.
• Give SaaS ops and automation engineers early warning signals with automatic, human-readable diagnostics.
• Maintain a historical record of refund/chargeback ratios in Google Sheets for reporting and review.

Technical details

• Integrations: Google Sheets, Slack, Google Gemini
• n8n nodes/tools: if, set, code, slack, sticky note, google sheets
• Core logic: 7-day ratio vs 90-day baseline, anomaly threshold multiplier, and “insufficient data” status handling