Track Personal Finances in Google Sheets with AI Agent via Slack

Description

Who's it for

This workflow is perfect for individuals who want to maintain detailed financial records without the overhead of complex budgeting apps. If you prefer natural language over data entry forms and want an AI assistant to handle the bookkeeping, this template is for you. It's especially useful for:

People who want to track cash and online transactions separately
Anyone who lends money to friends/family and needs debt tracking
Users comfortable with Slack as their primary interface
Those who prefer conversational interactions over manual spreadsheet updates

What it does

This AI-powered finance tracker transforms your Slack workspace into a personal finance command center. Simply mention your bot with transactions in plain English (e.g., "₹500 cash food, borrowed ₹1000 from John"), and the AI agent will:

Parse transactions using natural language understanding via Google Gemini
Calculate balance changes for cash and online accounts
Show a preview of changes before saving anything
Update Google Sheets only after you approve
Track debts (who owes you, who you owe, repayments)
Send daily reminders at 11 PM with current balances and active debts

The workflow maintains conversational context using PostgreSQL memory, so you can say things like "yesterday's transactions" or "that payment to Sarah" and it understands the context.

How it works

Scheduled Daily Check-in (11 PM)
Fetches current balances from Google Sheets
Retrieves all active debts
Formats and sends a Slack message with balance summary
Prompts you to share the day's transactions

AI Agent Transaction Processing
When you mention the bot in Slack:

Phase 1: Parse & Analyze
Extracts amount, payment type (cash/online), category (food, travel, etc.)
Identifies transaction type (expense, income, borrowed, lent, repaid)
Stores conversation context in PostgreSQL memory

Phase 2: Calculate & Preview
Reads current balances from Google Sheets
Calculates new balances based on transactions
Shows formatted preview with projected changes
Waits for your approval ("yes"/"no")

Phase 3: Update Database (only after approval)
Logs transactions with unique IDs and timestamps
Updates debt records with person names and status
Recalculates and stores new balances
Handles debt lifecycle (Active → Settled)

Phase 4: Confirmation
Sends success message with updated balances
Shows active debts summary
Includes logging timestamp

Requirements

Essential Services:
n8n instance (self-hosted or cloud)
Slack workspace with admin access
Google account
Google Gemini API key
PostgreSQL database

Recommended:
Claude AI model (mentioned in workflow notes as better alternative to Gemini)

How to set up

1. Google Sheets Setup

Create a new Google Sheet with three tabs named exactly:

Balances Tab:
| Date | Cash_Balance | Online_Balance | Total_Balance |
|------|--------------|----------------|---------------|

Transactions Tab:
| Transaction_ID | Date | Time | Amount | Payment_Type | Category | Transaction_Type | Person_Name | Description | Added_At |
|----------------|------|------|--------|--------------|----------|------------------|-------------|-------------|----------|

Debts Tab:
| Person_Name | Amount | Type | Date_created | Status | Notes |
|-------------|--------|------|--------------|--------|-------|

Add header rows and one initial balance row in the Balances tab with today's date and starting amounts.

2. Slack App Setup

Go to api.slack.com/apps and create a new app
Under OAuth & Permissions, add these Bot Token Scopes:
app_mentions:read
chat:write
channels:read
Install the app to your workspace
Copy the Bot User OAuth Token
Create a dedicated channel (e.g., #personal-finance-tracker)
Invite your bot to the channel

3. Google Gemini API

Visit ai.google.dev
Create an API key
Save it for n8n credentials setup

4. PostgreSQL Database

Set up a PostgreSQL database (you can use Supabase free tier):
Create a new project
Note down connection details (host, port, database name, user, password)
The workflow will auto-create the required table

5. n8n Workflow Configuration

Import the workflow and configure:

A. Credentials
Google Sheets OAuth2**: Connect your Google account
Slack API**: Add your Bot User OAuth Token
Google Gemini API**: Add your API key
PostgreSQL**: Add database connection details

B. Update Node Parameters

All Google Sheets nodes: Select your finance spreadsheet
Slack nodes: Select your finance channel
Schedule Trigger: Adjust time if you prefer a different check-in hour (default: 11 PM)
Postgres Chat Memory:
Change sessionKey to something unique (e.g., finance_tracker_your_name)
Keep tableName as n8n_chat_history_finance or rename consistently

C. Slack Trigger Setup
Activate the "Bot Mention trigger" node
Copy the webhook URL from n8n
In Slack App settings, go to Event Subscriptions
Enable events and paste the webhook URL
Subscribe to bot event: app_mention
Save changes

6. Test the Workflow

Activate both workflow branches (scheduled and agent)
In your Slack channel, mention the bot: @YourBot ₹100 cash snacks
Bot should respond with a preview
Reply "yes" to approve
Verify Google Sheets are updated

How to customize

Change Transaction Categories
Edit the AI Agent's system message to add/remove categories. Current categories:
travel, food, entertainment, utilities, shopping, health, education, other

Modify Daily Check-in Time
Change the Schedule Trigger's triggerAtHour value (0-23 in 24-hour format).

Add Currency Support
Replace ₹ with your currency symbol in:
Format Daily Message code node
AI Agent system prompt examples

Switch AI Models
The workflow uses Google Gemini, but notes recommend Claude. To switch:
Replace "Google Gemini Chat Model" node
Add Claude credentials
Connect to AI Agent node

Customize Debt Types
Modify AI Agent's system prompt to change debt handling logic:
Currently: I_Owe and They_Owe_Me
You can add more types or change naming

Add More Payment Methods
Current: cash, online
To add more (e.g., credit card):
Update AI Agent prompt
Modify Balances sheet structure
Update balance calculation logic

Change Approval Keywords
Edit AI Agent's Phase 2 approval logic to recognize different approval phrases.

Add Spending Analytics
Extend the daily check-in to calculate:
Weekly/monthly spending summaries
Category-wise breakdowns
Use additional Code nodes to process transaction history

Important Notes

⚠️ Never trigger with normal messages - Only use app mentions (@botname) to avoid infinite loops where the bot replies to its own messages.

💡 Context Awareness - The bot remembers conversation history, so you can reference "yesterday", "last week", or previous transactions naturally.

🔒 Data Privacy - All your financial data stays in your Google Sheets and PostgreSQL database. The AI only processes transaction text temporarily.

📊 Backup Regularly - Export your Google Sheets periodically as backup.

Pro Tips:
Start with small test transactions to ensure everything works
Use consistent person names for debt tracking
The bot understands various formats: "₹500 cash food" = "paid 500 rupees in cash for food"
You can batch transactions in one message: "₹100 travel, ₹200 food, ₹50 snacks"