How to Build an Automated Invoice Follow-Up System Using n8n

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A tutorial published on DEV Community walks freelancers and small business owners through building an automated invoice reminder workflow using n8n, a no-code automation tool. The system reads an unpaid invoice list from Google Sheets each morning and sends escalating email reminders at three thresholds: 3, 7, and 14 days overdue. A Slack alert is also triggered at the 14-day mark to flag invoices requiring personal attention. The workflow automatically skips invoices already contacted that day and stops all reminders once a client is marked as paid in the sheet. No coding experience is required, and the setup relies on a scheduled trigger, the Google Sheets API, and a simple JavaScript logic node to calculate days overdue.

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