n8n Workflow: Chase Overdue QuickBooks Invoices w/ Claude, Gmail, Slack

Automatically chase overdue QuickBooks Online invoices—with Claude-written emails and Slack visibility

This n8n workflow runs every weekday to find overdue QuickBooks Online invoices, chooses the correct reminder stage using your Google Sheets logs and do-not-chase list, drafts or sends Gmail reminders with opening/closing text written by Anthropic Claude, and posts escalation alerts and daily summaries to Slack.

What this workflow does

• Schedules & testing: Executes every weekday at 9:00 (or can be run manually with built-in sample data for testing).
• Finds what’s overdue: Pulls unpaid QuickBooks Online invoices past the due date.
• Stage selection & skipping rules: Reads the Reminder log and Do not chase tabs in Google Sheets, then applies stage rules, cooldown, minimum balance, and per-run limits to decide who gets reminded, who is escalated, and what’s skipped.
• Claude-assisted email text: Uses Anthropic Claude to write the email opening and closing for the selected stage, then assembles a plain-text message including the invoice table, totals, and payment instructions.
• Gmail send/draft behavior: Sends stage 1–3 reminders via Gmail (or saves based on your configured send mode). Final notices are always saved as Gmail drafts for review.
• Slack alerts & reporting: Posts one-time Slack alerts when invoices pass the escalation threshold, and publishes a daily Slack summary of totals, reminders, escalations, and skipped items.
• Audit trail in Google Sheets: Appends one row per affected invoice to the Reminder log (sent/drafted/failed reminders and Slack escalations).

Use cases

• SaaS finance teams automating overdue invoice reminders with consistent, staged messaging.
• Operations/automation engineers needing a reliable QuickBooks Online + Gmail + Slack escalation workflow.
• Companies that want human review before final dunning by saving final notices as Gmail drafts.

Technical details

• Integrations: QuickBooks Online, Google Sheets, Gmail, Slack, Anthropic (Claude)
• n8n nodes referenced: if, set, code, no op, gmail, slack