💸 Splitify

A beautiful local-first bill splitting app built with Expo + React Native.

Track shared expenses, see who owes whom, settle up faster, and keep everything on-device.

---

✨ Why Splitify?

Splitify is made for the moments when money gets awkward:

• a weekend trip with friends
• a shared apartment grocery run
• office lunch collections
• a movie night, cab ride, or coffee round

Instead of juggling screenshots, notes apps, and mental math, Splitify gives you one clean place to:

• create a group,
• add members,
• record expenses,
• split equally, exactly, or by percentage,
• and instantly see the simplest way to settle up.

Best part? Your data stays on your device. No login, no server, no cloud dependency.

---

🌟 Highlights

🔒 Local-first and private

All groups, expenses, and settlements are stored locally using react-native-mmkv through persisted Zustand stores. That means the app works without accounts or backend infrastructure.

🧮 Smart debt simplification

Splitify does not just total numbers — it calculates net balances and reduces them into a smaller set of “A pays B” settlements, making it easier for groups to close out debts.

👥 Flexible group setup

Create groups with:

• a custom name
• a fun emoji icon
• a custom currency symbol
• multiple members with auto-generated avatars

💵 Multiple split styles

When adding an expense, you can split it:

• Equally
• By exact amount
• By percentage

📦 Easy sharing and backup

Splitify supports:

• exporting a single group as a .spt file
• exporting all groups into a ZIP backup
• importing .spt files back into the app

🎨 Polished mobile experience

The app includes:

• custom bottom tab bar with floating action button
• light/dark theme support based on system settings
• native-feeling haptics on key interactions
• clean cards, avatars, and balance summaries

---

🧭 What you can do in the app

Home

• View overall balance across groups
• See your group previews
• Check recent activity from expenses and settlements

Groups

• Browse all groups
• Long-press a group to edit or delete it
• Prevent accidental deletion when unsettled balances still exist

Group Details

• See all members in a group
• View total spending
• Check simplified balances
• Add a new expense
• Share a group as a .spt file
• Open the settle-up flow

Add Expense

• Enter a description and total amount
• Choose who paid
• Select who participated
• Split by equal, exact, or percentage rules

Settle Up

• View who owes whom
• Record full or partial payments
• Watch the balance list update as debts are cleared

Activity

• Review expense history across groups

Settings

• Import a .spt group file
• Export all groups to a ZIP backup
• Clear all local data
• View app version and theme mode

---

🛠 Tech stack

• Framework: Expo + React Native
• Routing: Expo Router
• Language: TypeScript
• State management: Zustand
• Persistence: Zustand persist + react-native-mmkv
• Icons: lucide-react-native
• Animations: react-native-reanimated
• Haptics: expo-haptics
• File sharing/import: expo-sharing, expo-document-picker, expo-file-system, jszip
• Color generation: @material/material-color-utilities

---

📁 Project structure

splitify/
├── app/                  # Expo Router screens
│   ├── (tabs)/           # Home, Groups, Activity, Settings tabs
│   ├── group/            # Group details, add expense, settle-up screens
│   └── modals/           # Create/edit group flows
├── src/
│   ├── components/       # Reusable UI building blocks
│   ├── services/         # Split logic + import/export services
│   ├── store/            # Zustand stores + MMKV adapter
│   ├── theme/            # Colors, shadows, spacing, typography
│   ├── types/            # Shared TypeScript types
│   └── utils/            # Currency, date, avatar, ID helpers
├── app.json              # Expo app configuration
└── package.json          # Scripts and dependencies

---

🚀 Getting started

Prerequisites

Make sure you have:

• Node.js 18+
• npm
• Expo Go on your phone, or
• an Android emulator / iOS simulator for local testing

Installation

git clone https://github.com/soumya-99/splitify.git
cd splitify
npm install

Start the development server

npm run start

Then choose one of the following:

• press a to open Android
• press i to open iOS
• press w to open web
• or scan the QR code in Expo Go

---

📜 Available scripts

npm run start          # Start Expo dev server
npm run android        # Run on Android
npm run ios            # Run on iOS
npm run web            # Run on web
npm run prebuild       # Generate native projects
npm run prebuild:clean # Clean prebuild
npm run build:apk      # Android release build command
npm run lint           # Run Expo/ESLint checks

---

🧠 How settlement calculation works

Splitify keeps track of:

1. expenses — who paid and how the cost was split
2. settlements — payments recorded later between members

From that, it computes each member’s net balance:

• if someone paid more than their share, they become a creditor
• if someone paid less than their share, they become a debtor

The app then simplifies debts into a minimal-style payment list such as:

• Alice pays Bob ₹250
• Carol pays Dan ₹120

This keeps settlement suggestions easier to follow than a raw expense-by-expense ledger.

---

💾 Data import/export

Splitify supports portable group files:

.spt file

A single exported group contains:

• app export version
• group metadata
• all expenses in that group
• all recorded settlements in that group

ZIP backup

The app can also package every group into a ZIP archive so you can back up all your local ledgers at once.

Import behavior

When importing a .spt file, Splitify checks for duplicate group IDs and avoids importing the same group twice.

---

🎨 Design notes

A few implementation details that make the app feel more refined:

• avatars use Material color utilities to generate pleasant, distinct colors from names
• the app follows the device’s system theme automatically
• interactions such as add/save/select trigger haptic feedback
• the custom bottom tab bar includes a centered floating action button for quick group creation

---

⚠️ Current behavior to know

These are not necessarily problems, just useful product notes based on the current implementation:

• The app is local-first — there is no account sync or remote backup.
• Theme selection is automatic and follows the system theme.
• Group deletion is blocked when unresolved balances still exist.
• The first member added during group creation starts as “You” by default.

---

🤝 Contributing

Contributions are welcome.

If you want to improve the app:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Run lint checks
5. Open a pull request

Example:

git checkout -b feat/improve-readme
npm run lint
git commit -m "docs: improve README"

---

📄 License

This project is licensed under the MIT License. See LICENSE for details.

---

💜 Closing note

Splitify is the kind of app that tries to stay out of your way: fast to open, simple to use, and clear when money gets messy.

If you like the idea, star the project and make it your go-to shared expense tracker.