SplitMint

SplitMint is a modern group expense-splitting web application that helps users create groups, add shared expenses, track balances, and view simplified settlement suggestions.

The app also includes MintSense, an AI-assisted feature that can parse natural-language expense entries and convert them into structured expenses.

Live Demo

Deployed App: https://splitmint-steel.vercel.app

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Features

• Email/password authentication
• Google OAuth login
• Create and manage expense groups
• Add participants to a group
• Add expenses manually
• Select payer and split participants
• Equal split calculation
• Balance calculation for each participant
• Settlement suggestions to minimize repayments
• MintSense AI for natural-language expense entry
• INR currency display with ₹
• Responsive mint-themed UI
• Supabase database integration
• Supabase Edge Function for AI parsing
• Vercel deployment

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Example Flow

1. User signs in using email/password or Google.
2. User creates a group, for example Coorg.
3. User adds participants like A, B, and C.
4. User adds an expense manually, for example:
   • Description: Dinner
   • Amount: ₹1000
   • Paid by: You
   • Split between: You, A, B, C
5. SplitMint calculates:
   • Total spent
   • Individual balances
   • Who owes whom
6. User can also use MintSense:
   • Input: I paid 800 for lunch today split with A, B and C
   • Output: A structured expense is automatically added.

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Tech Stack

Frontend

• React
• TypeScript
• Vite
• TanStack Router / TanStack Start
• Tailwind CSS
• Radix UI
• Lucide React
• Sonner

Backend / Database

• Supabase
• Supabase Auth
• Supabase PostgreSQL
• Supabase Row Level Security
• Supabase Edge Functions

AI

• MintSense AI via Supabase Edge Function
• OpenAI-compatible chat completions endpoint
• Gemini API-compatible configuration

Deployment

• Vercel
• Supabase Cloud

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Project Structure

SplitMint
├── src
│   ├── components
│   │   ├── AppShell.tsx
│   │   └── ui
│   ├── hooks
│   │   └── useAuth.tsx
│   ├── integrations
│   │   └── supabase
│   ├── lib
│   │   ├── balance.ts
│   │   └── utils.ts
│   ├── routes
│   │   ├── __root.tsx
│   │   ├── auth.tsx
│   │   ├── dashboard.tsx
│   │   ├── groups.$groupId.tsx
│   │   └── index.tsx
│   ├── router.tsx
│   ├── routeTree.gen.ts
│   └── styles.css
├── supabase
│   ├── functions
│   │   └── mintsense
│   │       └── index.ts
│   └── migrations
├── package.json
├── vite.config.ts
├── tsconfig.json
└── README.md

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Core Logic

The main balance and settlement calculations are handled in:

src/lib/balance.ts

The app calculates:

• Total group spending
• Net balance for each participant
• Who should pay whom
• Simplified settlement suggestions

Example:

If one person pays ₹1000 for 4 people:

₹1000 / 4 = ₹250 per person
Payer's own share = ₹250
Other 3 participants owe ₹250 each
Payer's net balance = +₹750

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MintSense AI

MintSense allows users to enter expenses using natural language.

Example input:

I paid 800 for lunch today split with A, B and C

Expected result:

Description: lunch
Amount: ₹800
Paid by: current user
Split between: current user, A, B, C
Split mode: equal

MintSense is implemented as a Supabase Edge Function:

supabase/functions/mintsense/index.ts

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Environment Variables

Create a .env file using .env.example as reference.

SUPABASE_PUBLISHABLE_KEY=your_supabase_publishable_key_here
SUPABASE_URL=your_supabase_url_here
VITE_SUPABASE_PROJECT_ID=your_supabase_project_id_here
VITE_SUPABASE_PUBLISHABLE_KEY=your_supabase_publishable_key_here
VITE_SUPABASE_URL=your_supabase_url_here

For Supabase Edge Function AI support, set these secrets in Supabase:

AI_API_KEY=your_ai_api_key_here
AI_API_URL=your_openai_compatible_chat_completions_url_here
AI_MODEL=your_ai_model_here

Example:

AI_API_URL=https://generativelanguage.googleapis.com/v1beta/openai/chat/completions
AI_MODEL=gemini-3-flash-preview

Do not commit real API keys or secrets to GitHub.

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Local Setup

1. Clone the repository

git clone https://github.com/gokularaman-c/Splitmint.git
cd Splitmint

2. Install dependencies

npm install

3. Create .env

Create a .env file in the root directory and add your Supabase values:

SUPABASE_PUBLISHABLE_KEY=your_supabase_publishable_key_here
SUPABASE_URL=your_supabase_url_here
VITE_SUPABASE_PROJECT_ID=your_supabase_project_id_here
VITE_SUPABASE_PUBLISHABLE_KEY=your_supabase_publishable_key_here
VITE_SUPABASE_URL=your_supabase_url_here

4. Run the development server

npm run dev

The app will usually run at:

http://localhost:3000

or:

http://localhost:5173

depending on the available port.

5. Build the project

npm run build

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Supabase Setup

1. Create a Supabase project

Create a new project in Supabase and copy:

• Project URL
• Publishable key
• Project reference ID

2. Apply database migration

Run the SQL migration from:

supabase/migrations

You can apply it through:

Supabase Dashboard → SQL Editor → New Query → Paste SQL → Run

3. Configure authentication

Enable:

• Email/password authentication
• Google OAuth provider

For Google OAuth, configure:

Supabase → Authentication → Sign In / Providers → Google

Add:

• Google Client ID
• Google Client Secret

4. Configure redirect URLs

In Supabase:

Authentication → URL Configuration

Set Site URL:

https://splitmint-steel.vercel.app

Add redirect URLs:

https://splitmint-steel.vercel.app/**
https://splitmint-steel.vercel.app/dashboard
https://splitmint-steel.vercel.app/auth
http://localhost:3000/**
http://localhost:3000/dashboard

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Supabase Edge Function Setup

1. Install Supabase CLI

brew install supabase/tap/supabase

2. Login to Supabase

supabase login

3. Link the project

supabase link --project-ref your_project_ref

4. Deploy MintSense function

supabase functions deploy mintsense

5. Set AI secrets

supabase secrets set \
  AI_API_KEY="your_ai_api_key_here" \
  AI_API_URL="your_openai_compatible_chat_completions_url_here" \
  AI_MODEL="your_ai_model_here"

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Vercel Deployment

The app is deployed using Vercel.

Build command

npm run build

Install command

npm install

Output

The project uses TanStack Start with Nitro. The Vercel deployment should use the Nitro-compatible output generated during build.

The Vite config includes Nitro support:

import { nitro } from "nitro/vite";

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Current Status

The current version supports:

• Working production deployment
• Google login
• Email/password login
• Group creation
• Manual expense creation
• AI-based expense creation through MintSense
• Balance calculation
• Settlement suggestions
• INR currency display

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Future Improvements

• Add multiple split modes with richer validation
• Add expense editing history
• Add group invite links
• Add recurring expenses
• Add export to CSV/PDF
• Add dashboard analytics
• Add multi-currency support
• Improve MintSense summaries
• Add mobile-first PWA support

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Author

Gokularaman C