Credit Jambo Client Application

A comprehensive savings management system with secure authentication, device verification, and real-time transaction tracking.

Features

Backend (Node.js + Express + PostgreSQL)

• Secure Authentication: SHA-512 password hashing with JWT tokens
• Device Verification: Admin-controlled device access
• Savings Management: Deposit, withdraw, balance tracking
• Transaction History: Complete audit trail with pagination
• Security: Helmet, rate limiting, CORS, input validation
• API Documentation: Swagger/OpenAPI at /api-docs
• Testing: Comprehensive Jest test suite
• Docker Support: Full containerization

Frontend (React Native + Expo)

• Mobile App: Cross-platform iOS/Android/Web
• State Management: Redux Toolkit with persistent storage
• Secure Storage: Expo SecureStore for tokens
• Modern UI: Clean, intuitive interface
• Real-time Updates: Live balance and transaction updates
• Navigation: Bottom tabs with stack navigation

Architecture

credit-jambo-client/
├── backend/                 # Node.js API Server
│   ├── src/
│   │   ├── controllers/    # API endpoints
│   │   ├── models/         # Database models
│   │   ├── middlewares/    # Authentication & security
│   │   ├── utils/         # Helper functions
│   │   └── dtos/          # Data transfer objects
│   ├── tests/             # Jest test suite
│   ├── Dockerfile         # Container configuration
│   └── README.md          # Backend documentation
├── frontend/              # React Native App
│   ├── src/
│   │   ├── pages/         # Screen components
│   │   ├── navigation/    # App navigation
│   │   ├── store/         # Redux store
│   │   └── services/      # API integration
│   ├── Dockerfile         # Container configuration
│   └── README.md          # Frontend documentation
├── docker-compose.yml     # Full stack orchestration
└── README.md              # This file

Quick Start

Prerequisites

• Node.js (v16+)
• PostgreSQL (v12+)
• Docker & Docker Compose (optional)

Option 1: Docker (Recommended)

# Clone the repository
git clone <repository-url>
cd credit-jambo-client

# Start the entire stack
docker-compose up -d

# Backend API: http://localhost:4000
# API Docs: http://localhost:4000/api-docs
# Frontend: http://localhost:3000

Option 2: Local Development

# Backend
cd backend
npm install
cp .env.example .env
# Update .env with your database credentials
npm run dev

# Frontend (in another terminal)
cd frontend
npm install
cp .env.example .env
npm start

Security Features

• SHA-512 Password Hashing: Secure password storage
• JWT Authentication: Stateless token-based auth
• Device Verification: Admin-controlled access
• Rate Limiting: API abuse prevention
• Input Validation: Comprehensive data sanitization
• CORS Protection: Cross-origin request security
• Secure Headers: Helmet.js security middleware

User Flow

1. Registration: User creates account with device ID
2. Device Verification: Admin verifies the device
3. Login: User can access app after verification
4. Savings Management: Deposit, withdraw, view balance
5. Transaction History: Complete audit trail

Testing

# Backend tests
cd backend
npm test
npm run test:coverage

# Frontend tests
cd frontend
npm test

API Endpoints

Authentication

• POST /api/auth/register - User registration
• POST /api/auth/login - User login
• GET /api/auth/me - Get user profile
• POST /api/auth/logout - User logout

Savings (Requires Verified Device)

• POST /api/savings/deposit - Deposit money
• POST /api/savings/withdraw - Withdraw money
• GET /api/savings/balance - Get current balance
• GET /api/savings/history - Get transaction history

Docker Commands

# Build and start all services
docker-compose up -d

# View logs
docker-compose logs -f

# Stop services
docker-compose down

# Rebuild services
docker-compose up --build

# Run tests in container
docker-compose exec backend npm test

Environment Variables

Backend (.env)

PORT=4000
NODE_ENV=development
DB_HOST=localhost
DB_PORT=5432
DB_NAME=credit_jambo_client
DB_USER=your_username
DB_PASSWORD=your_password
JWT_SECRET=your-secret-key
CORS_ORIGIN=http://localhost:3000

Frontend (.env)

EXPO_PUBLIC_API_URL=http://localhost:4000/api
EXPO_PUBLIC_APP_NAME=Credit Jambo

Built with ❤️ by Iris NGABO