Track and analyze Google Sheets expenses with Gemini and Gmail alerts

Expense Leak Detector

Smart Expense Monitoring in Minutes

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This n8n workflow reads your expenses from Google Sheets, categorizes them using predefined keywords, summarizes spending per category, generates AI-powered financial advice using Gemini, stores results in another sheet and sends email alerts for high or normal expenses.

Quick Start Guide

1. Import the workflow into n8n

2. Connect:

• Google Sheets OAuth2
• Google Gemini API
• Gmail OAuth2

3. Update the Settings node:

• Budget limit
• Recipient email
• Sender name

4. Ensure:

• Sheet1 → Date, Description, Amount
• Sheet2 → Date, Category, Total Spent, AI Report, Status, Reviewed On

5. Click "Execute Workflow"

What It Does

This workflow automates your expense tracking and financial analysis using a combination of Google Sheets and AI.

It begins by fetching raw expense data from a Google Sheet (Sheet1), where each row contains a date, description and amount. The workflow then processes each row by cleaning the data and assigning a category such as Food, Transport, Subscription, Shopping, Utilities, Health or Other using predefined keyword matching.

Once categorized, it aggregates total spending per category and evaluates whether the spending exceeds a defined budget limit. Based on this evaluation, it generates a detailed, personalized financial advisory report using Google Gemini AI.

Finally, the workflow stores all results in another sheet (Sheet2) and sends an email notification—either a high expense alert or a normal summary—based on the spending status.

Who’s It For

• Individuals managing personal finances
• Freelancers tracking monthly expenses
• Families monitoring household spending
• Finance enthusiasts wanting AI-driven insights
• Anyone using Google Sheets for expense tracking

Requirements

To use this workflow, you need:

• n8n (self-hosted or cloud)
• Google Sheets account
• Google Gemini API key
• Gmail account (for sending emails)
• A Google Sheet with:
• Sheet1: Expense data
• Sheet2: Output report

How To Set Up

1. Import Workflow

Import the provided JSON file into n8n

2. Connect Credentials

• Google Sheets OAuth2 → For reading and writing data
• Google Gemini API → For AI report generation
• Gmail OAuth2 → For sending emails

3. Prepare Google Sheets

Sheet1 (Input)

Date	Description	Amount

Sheet2 (Output)

Date	Category	Total Spent	AI Report	Status	Reviewed On

4. Configure Settings Node

Update the “Settings — Change These Before Running” node:

• Budget Limit → Threshold for high expense detection
• Send Report To Email → Recipient email
• Email Sender Name → Display name
• Currency Symbol → Example: Rs.
• Report Period → Example: This Month

5. Run Workflow

• Click “Execute Workflow”
• The workflow will:
• Read expenses
• Categorize them
• Generate AI insights
• Save results
• Send email alerts

How It Works (Step-by-Step Flow)

1. Manual Trigger

• Starts the workflow

2. Read Expenses

• Fetches rows from Sheet1

3. Settings Node

• Stores all configurable values

4. Clean & Categorize

• Converts description to lowercase
• Assigns categories using hardcoded keyword logic

5. Summarize

• Groups data by category
• Calculates total spend

6. Build AI Fields

• Prepares structured input for Gemini

7. Gemini AI

• Generates detailed financial advisory report

8. Collect Data

• Formats data for storage and email

9. Save to Sheet2

• Appends results

10. Condition Check

• Determines if expense is high or normal

11. Email Notifications

• Sends:
• High Expense Alert OR
• Normal Summary

How To Customize Nodes

1. Categorization Logic

• Modify the “Clean and Categorise Each Expense Row” node
• Add or update keyword checks for categories

2. Budget Threshold

• Change Budget Limit in Settings node

3. AI Prompt

• Edit “Ask Gemini to Write Expense Report”
• Customize tone, format or advice style

4. Email Content

• Modify:
• Subject lines
• Email body
• Sender name

5. Currency & Region

• Update:
• Currency symbol
• Date format (if needed)

Add-Ons (Enhancements)

• Add Cron Trigger for automatic daily/monthly runs
• Integrate Slack/WhatsApp alerts
• Add dashboard visualization (Google Data Studio / Looker)
• Store reports in Notion or Airtable
• Add multi-user expense tracking
• Enable PDF report generation

Use Case Examples

1. Monthly Personal Expense Review

• Automatically analyze and summarize monthly spending

2. High Spending Alerts

• Get notified when a category exceeds your budget

3. Subscription Cost Optimization

• Identify unnecessary recurring expenses

4. Family Budget Monitoring

• Track combined household expenses

5. Freelancer Expense Tracking

• Monitor business vs personal expenses

There can be many more variations of this workflow depending on your needs.

Troubleshooting Guide

Issue	Possible Cause	Solution
No data fetched	Incorrect Sheet ID or tab	Verify Sheet1 configuration
Categories not accurate	Keyword mismatch	Update categorization logic
AI report not generated	Invalid Gemini API key	Reconnect API credentials
Emails not sent	Gmail not connected	Reauthorize Gmail OAuth
Sheet2 not updating	Column mismatch	Ensure correct headers
Always "Normal Expense"	Budget too high	Adjust Budget Limit
Missing email recipient	Email not set in Settings	Add recipient email

Need Help?

If you need help setting up, customizing or extending this workflow, we’re here to support you.

Whether you want:

• Advanced automation
• Custom AI workflows
• Business process optimization
• Integration with your existing systems

Reach out to WeblineIndia for expert assistance in building powerful, scalable automation solutions tailored to your needs.