Invoice Creator with Google Sheets & Automated Email Payment Reminder System

Description

This automated n8n workflow streamlines invoice creation and payment reminders. It generates invoices on a monthly schedule and sends reminders for overdue payments, updating records in Google Sheets.

Good to Know
Supports monthly invoice generation and daily overdue checks
Integrates with Google Sheets for data management
Uses email notifications for invoice delivery and reminders
Includes logging for tracking and auditing
Features multiple reminder types based on overdue duration

How It Works
Invoice Creation Flow:
Monthly Invoice Trigger** - Initiates workflow on a set monthly schedule
Get Clients for Invoicing** - Reads client data from Google Sheet
Filter Active Clients** - Filters out inactive clients
Generate Invoice Data** - Creates invoice details in required format
Save Invoice to Google Sheets** - Appends or updates invoice record in the sheet
Send Invoice Email** - Sends the invoice to the client via email
Log Invoice Creation** - Logs invoice creation for records/auditing

Reminder Flow:
Daily Payment Reminder Check** - Triggers workflow daily to check overdue invoices
Get Overdue Invoices** - Reads overdue invoices from Google Sheet
Filter Overdue Invoices** - Filters invoices still unpaid
Calculate Reminder Type** - Calculates how many days overdue
Switch Reminder Type** - Decides which type of reminder to send
Send Gentle / Follow-up / Urgent / Final Notice** - Sends respective reminder email
Update Reminder Log** - Updates reminder status in the sheet

How to Use
Import workflow into n8n
Configure Google Sheets API for data access
Set up email service for notifications
Define monthly schedule for invoice trigger
Test with sample client data and monitor reminders
Adjust reminder thresholds as needed

Requirements
Access to Google Sheets API
Email service configuration
Scheduled trigger setup in n8n

Sheet Columns:
Client Name**
Invoice ID**
Amount**
Due Date**
Status**
Reminder Type**
Last Updated**

Customizing This Workflow
Modify invoice generation schedule
Adjust reminder email templates
Configure custom Google Sheet columns
Set custom overdue thresholds
Integrate additional notification methods