Automate Invoice Chasing with n8n: Google Sheets + Gmail + Claude

Automatically chase unpaid invoices—using Google Sheets, Gmail, and Claude

This n8n workflow reads your unpaid invoices from Google Sheets, checks your most recent client conversations in Gmail, and uses Claude (Anthropic) to decide whether to send a reminder, snooze, escalate, or skip. You also receive an HTML daily digest summarizing what happened—optionally with quick action links.

What this workflow does

• Runs on schedule, manually, or via webhook to support digest actions.
• Selects which invoices need follow-up today based on due dates, current status, snoozes, and minimum spacing between reminders.
• Pulls recent Gmail messages for each client and creates a cleaned conversation timeline for the relevant invoice context.
• Uses Claude to make the next move when the situation isn’t clear—choosing SEND, SNOOZE, ESCALATE, or SKIP, and optionally rewriting the reminder body.
• Applies guardrails to avoid missing invoice IDs, links, or placeholders in the generated reminder.
• Sends or drafts reminders in Gmail depending on your auto-send setting, and updates Google Sheets with last sent time, last follow-up date, snooze/escalation/skip status, and notes.
• Sends you an HTML daily digest of outcomes (with optional one-tap action links).

Use cases

• Reduce manual invoice chasing for SaaS subscriptions and services.
• Keep reminder frequency consistent with minimum spacing rules.
• Use email context to prevent repetitive or inappropriate follow-ups.
• Centralize tracking of reminder history directly in Google Sheets.

Technical details

• Integrations: Google Sheets, Gmail
• AI: Anthropic Claude (decision + optional rewrite)
• n8n logic: if, code, switch, webhook, and split-out behavior