SplitWise - Expense Splitting App

SplitWise is a full-stack application designed to simplify the process of tracking and splitting expenses with friends and groups. This project features a modern Android application built with Jetpack Compose and a robust backend infrastructure.

The backend is a custom-built API developed using TypeScript and NestJS, deployed in the cloud to provide a seamless, real-time experience for users.

Note: This repository contains the Android client code. The backend source code is maintained in a separate repository.

📸 Screenshots

Onboarding & Authentication

Onboarding	Login	Signup

Main Experience

Dashboard	Activity Feed	Friends List

Bill Management

Settle Bill	Send Reminder	User Profile

Multi-step Bill Creation

Step 1: Details	Step 2: Participants	Step 4: Payer

Step 5: Split Method	Step 6: Adjustments	Step 7: Review

🚀 Features

Core Functionality

• Adaptive UI Support: Fully responsive across all Window Size Classes, ensuring a seamless experience on phones, foldables, and tablets. Optimized for both Portrait and Landscape orientations to provide an ergonomic user experience across diverse device configurations.
• Multi-step Bill Creation: A guided 7-step process to add bills, select participants, define payers, and choose split methods.
• Flexible Splitting: Support for various split methods including:
  • Equal: Automatically divides the total amount among all participants.
  • Percentage: Define custom percentages for each individual.
  • Exact Amount: Specify precise amounts for each participant.
• Group & Friend Management: Organize expenses by specific groups or individual friends.
• Dashboard & Activity: Track your total balance (owed vs. owing) and view a real-time activity feed of all transactions.

Account & Security

• Secure Authentication: Robust login and signup flows with encrypted token storage.
• Profile Management: Update personal information and manage account settings.
• Firebase Integration: Push notifications via Firebase Cloud Messaging (FCM) for bill reminders and activity updates.
• Privacy Controls: Secure password changes and account deletion options.
• Code Protection: Integrated R8/ProGuard rules for code obfuscation and shrinking.

🛠 Tech Stack

Android (Frontend)

• UI: Jetpack Compose - Modern, declarative UI toolkit.
• Architecture: MVVM (Model-View-ViewModel) with Clean Architecture principles.
• Dependency Injection: Hilt - Standard library for DI in Android.
• Networking: Retrofit & OkHttp for REST API communication.
• Reactive Programming: Kotlin Coroutines and Flow for asynchronous data handling.
• Pagination: Paging 3 for efficient loading of large activity feeds and bill lists.
• Local Storage: DataStore & EncryptedSharedPreferences for secure data persistence.
• Security & Optimization: R8/ProGuard for code shrinking, obfuscation, and optimization.
• Backend Services: Firebase Analytics, Crashlytics, and Cloud Messaging.

Backend

• Framework: NestJS (Node.js framework)
• Language: TypeScript
• Deployment: Cloud-hosted API
• Repository: Private/Separate repository

🏗 Project Structure

The project follows a feature-based package structure for high maintainability:

com.omodauda.splitwise
├── data
│   ├── local        # DataStore, Preferences, Encrypted Storage
│   ├── network      # API Interfaces, DTOs, Interceptors, Paging Sources
│   └── repository   # Single source of truth for data logic
├── di               # Hilt Modules (Network, Storage, etc.)
├── model            # Domain models and UI state classes
├── services         # Firebase Messaging Service
└── ui
    ├── components   # Reusable UI widgets (Buttons, Toasts, Loaders)
    ├── features     # Feature-specific screens and ViewModels
    │   ├── auth     # Login, Signup, Forgot Password
    │   └── main     # Dashboard, Add Bill, Groups, Friends, Activity
    └── theme        # Material3 Design System (Color, Typography, Shape)

🚦 Getting Started

Prerequisites

• Android Studio Ladybug or newer.
• JDK 11+.
• A local.properties file containing your BASE_URL.
• A google-services.json file in the app/ directory (required for Firebase features).

Installation

1. Clone the repository.
2. Add your BASE_URL to the local.properties file.
3. Place your google-services.json in the app/ folder.
4. Sync the project with Gradle files.
5. Run the app on an emulator or physical device.

📈 Future Roadmap

• Offline support with Room database.
• Unit and UI testing suite.
• Group management (creation, editing, member management).
• Group-specific expense tracking and settlements.
• Image upload support for receipts.
• Dynamic deep linking for group invites.

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Developed as a showcase of modern Android development practices.