LazyLedger

Automate your personal expense tracking - from HDFC SMS to Notion + Splitwise, in under 10 seconds.

Built for the Indian UPI/HDFC ecosystem. No third-party apps, no subscriptions, no servers. Just your phone, Google Apps Script, and a Notion database.

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What it does

When you pay: HDFC SMS arrives -> iPhone Shortcut fires automatically -> you confirm description, category, and whether it's shared (10 seconds) -> entry created in Notion + Splitwise updated if shared.

When your flatmate pays: They log to Splitwise -> Google Apps Script polls every hour -> Notion entry auto-created -> you get an email to set the category.

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Stack

Component	Tool	Cost
SMS trigger	iPhone Shortcuts (iOS 16.5+)	Free
Expense database	Notion API	Free
Shared expense tracking	Splitwise API	Free
Flatmate sync	Google Apps Script	Free
Notifications	Gmail	Free

Total cost: ₹0/month

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Architecture

┌─────────────────────────────────────────────────────┐
│                    FLOW 1: YOU PAY                  │
│                                                     │
│  HDFC SMS -> iPhone Shortcut -> [10-sec prompt]     │
│                ↓                    ↓               │
│           Notion DB           Splitwise             │
│         (always)           (if shared)              │
└─────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────┐
│                 FLOW 2: FLATMATE PAYS               │
│                                                     │
│  Flatmate -> Splitwise -> Google Apps Script        │
│                         (polls hourly via API)      │
│                              ↓                      │
│                         Notion DB                   │
│                    + Email notification             │
└─────────────────────────────────────────────────────┘

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Prerequisites

• iPhone with iOS 16.5+ and Shortcuts app
• HDFC Bank account (SMS alerts enabled)
• Notion account (free tier)
• Splitwise account (free tier)
• Google account (for Apps Script)

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Setup Guide

1. Notion Setup

1. Go to notion.so/my-integrations
2. Create a new integration -> name it Expense Tracker
3. Copy the Internal Integration Secret (secret_xxx...)
4. Create your monthly expense database with these properties:

Property	Type	Options
Description	Title	-
Date	Date	-
Amount	Number	Rupee format
Category	Multi-select	See category list below
Payment Method	Select	Phone Pe, CRED UPI, Credit Card

5. Share the database with your integration (... menu -> Connections)
6. Copy the Database ID from the URL (32-character string after the last /)

Category list:

Groceries and Veggies
Outside food
Rent
Cook
WiFi & Internet Bills
Fuel
Entertainment
Skincare
Transportation
Others

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2. Splitwise Setup

1. Go to secure.splitwise.com/apps/new
2. Register a new app -> name it Expense Tracker -> URL: https://localhost
3. Click Create API key -> copy the key

Get your IDs via terminal:

# Your user ID
curl -H "Authorization: Bearer YOUR_API_KEY" \
  https://secure.splitwise.com/api/v3.0/get_current_user

# Your group ID + flatmate's user ID
curl -H "Authorization: Bearer YOUR_API_KEY" \
  https://secure.splitwise.com/api/v3.0/get_groups

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3. iPhone Shortcut Setup

See shortcut/reference.md for the complete step-by-step guide.

Trigger: Message containing From HDFC Bank A/C *XXXX (your last 4 digits)

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4. Google Apps Script Setup

1. Go to script.google.com -> New Project
2. Paste the contents of google-apps-script/splitwise-to-notion.gs
3. Fill in your credentials in the CONFIG object at the top
4. Run testScript first to verify all connections
5. Set up a trigger: syncSplitwiseToNotion -> Time-driven -> Every hour

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Configuration

All credentials go in the CONFIG object in splitwise-to-notion.gs:

const CONFIG = {
  SPLITWISE_API_KEY:  "your_splitwise_api_key",
  SPLITWISE_GROUP_ID: "your_group_id",
  ANUP_USER_ID:       "flatmate_user_id",
  NOTION_SECRET:      "secret_xxx",
  NOTION_DATABASE_ID: "your_database_id",
  YOUR_EMAIL:         "your@email.com",
};

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Monthly Maintenance (30 seconds)

At the start of each month:

• Create new monthly Notion database
• Share it with your Notion integration
• Copy the new database ID
• Update database_id in the Shortcut (Notion JSON body action)
• Update NOTION_DATABASE_ID in the Apps Script CONFIG

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How the Flatmate Sync Works

The Google Apps Script:

1. Calls GET /api/v3.0/get_expenses?group_id=YOUR_GROUP_ID
2. Filters for expenses created by your flatmate since the last run
3. Auto-detects category from description keywords (Blinkit -> Groceries, Zomato -> Outside food, etc.)
4. Creates a Notion entry - with ⚠️ [FLATMATE] prefix if category is ambiguous
5. Emails you with a direct link to review

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Keyword -> Category Mapping

Extend this in the KEYWORD_MAP object in the script:

Keyword	Category
blinkit, zepto, swiggy instamart	Groceries and Veggies
swiggy, zomato, restaurant	Outside food
rent	Rent
cook, maid	Cook
wifi, internet, broadband	WiFi & Internet Bills
petrol, fuel	Fuel
netflix, spotify, prime	Entertainment

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Security Notes

• Never commit your API keys to the repo
• Regenerate Splitwise API key periodically
• Notion integration secret is scoped only to databases you explicitly share with it
• Google Apps Script runs under your Google account with minimal permissions (URL fetch + Gmail)

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License

MIT - use it, fork it, improve it.