Automated Overdue Invoice Email Reminders (n8n, Gmail, Google Sheets)

Automated Overdue Invoice Email Reminders from Google Sheets (n8n + Gmail)

This n8n workflow automatically checks your Google Sheets invoices every morning, identifies which payments are overdue, generates the correct reminder message (first, second, or final), and sends it to your clients via Gmail.

What this workflow does

• Runs on a schedule: Executes every day at 9:00 using an n8n Schedule Trigger.
• Loads settings: Pulls configuration such as your Google Sheet ID, business details, date format, and reminder day thresholds.
• Reads invoice data: Loads all rows from the “Invoices” tab in Google Sheets.
• Determines overdue reminders: Parses Due Date, checks exact days overdue, assigns invoices to a first/second/final reminder stage based on status and thresholds, and skips rows with missing/invalid email, amount, or due date.
• Generates email content: Creates a plain-text subject and body from a fixed template using invoice details and the reminder stage.
• Sends via Gmail: Emails the reminder to the client using the gmail node.

Use cases

• SaaS operators who track billing in Google Sheets and want automatic overdue reminders without manual outreach.
• Freelancers and small businesses needing staged payment follow-ups (first/second/final) sent automatically.
• Automation engineers setting up a reliable accounts receivable reminder process with n8n.

Technical details

• n8n nodes / tech stack: set, code, gmail, google sheets, schedule trigger
• Google Sheets integration: Reads the Invoices tab with columns for Invoice Number, Client Name, Client Email, Status, Amount, and Due Date.
• Gmail integration: Uses Gmail to send the reminder emails to client addresses.

Setup

• Connect Google Sheets and set the sheet ID in the Settings step.
• Connect Gmail and ensure the workflow is allowed to send mail.
• Update Settings values (businessName, senderName, currencySymbol, dateFormat, and reminder day thresholds) to match your locale and billing rules.