Automated Invoice Follow-ups with Smart Response Tones via Google Sheets & Email

This n8n workflow automates the process of sending invoice follow-up emails. It periodically checks a Google Sheet for outstanding invoices, processes the data, and then sends personalized email reminders.

What it does

1. Triggers on a Schedule: The workflow starts on a predefined schedule (e.g., daily, weekly) using the Cron node.
2. Reads Invoice Data: It connects to a specified Google Sheet to retrieve a list of invoices, likely including details such as customer name, email, invoice amount, due date, and possibly a status or last follow-up date.
3. Processes Data (Placeholder): A "Function" node is included, which typically allows for custom JavaScript logic. In this context, it would likely be used to filter invoices that require follow-up, calculate overdue days, or format data for the email.
4. Sends Follow-up Emails: For each relevant invoice, it sends a personalized email using the "Send Email" node. The content of these emails would be dynamically generated based on the invoice data, potentially adjusting the tone or urgency based on how overdue the invoice is.

Prerequisites/Requirements

• n8n Instance: A running n8n instance.
• Google Sheets Account: An account with access to the Google Sheet containing your invoice data.
• Google Sheets Credentials: OAuth 2.0 credentials configured in n8n to allow access to your Google Sheets.
• SMTP Server Access: Credentials for an SMTP server to send emails (e.g., Gmail, SendGrid, your own mail server).

Setup/Usage

1. Import the Workflow: Import the provided JSON into your n8n instance.
2. Configure Cron Trigger: Adjust the "Cron" node to your desired schedule for checking invoices (e.g., once a day, every Monday).
3. Configure Google Sheets Node:
   • Select your Google Sheets credential.
   • Specify the Spreadsheet ID and Sheet Name where your invoice data is located.
   • Ensure the "Operation" is set to "Read" and configure any necessary filters or ranges to fetch the correct data.
4. Configure Function Node:
   • Crucial Step: The "Function" node currently acts as a placeholder. You will need to add custom JavaScript code here. This code should:
     • Iterate through the items received from Google Sheets.
     • Implement logic to determine which invoices need follow-up (e.g., based on due_date and last_follow_up_date).
     • Prepare the data for the email, potentially generating the email subject and body, and setting a "tone" (e.g., "polite", "firm") based on the overdue status.
     • Output items that should proceed to the "Send Email" node.
5. Configure Send Email Node:
   • Select your "Send Email" (SMTP) credential.
   • Dynamically set the To, Subject, and Body fields using expressions that reference the data output from the "Function" node (e.g., {{ $json.email }}, {{ $json.subject }}, {{ $json.body }}).
   • Ensure the email content includes relevant invoice details and a clear call to action.
6. Activate the Workflow: Once configured, activate the workflow to start the automated follow-up process.