Stay stress-free with your credit cards.

CardZen is a production-ready personal credit card management system built to solve the real problem of tracking expenses, billing cycles, cashback, money owed by others, and annual fee waivers across multiple credit cards.

• 🃏 Multi-card Management — Add unlimited credit cards with full configuration
• 💸 Expense Tracking — Log transactions with categories, platforms, and merchants
• 📅 Billing Cycle Intelligence — Auto-calculates current cycle, due dates, and outstanding amounts
• 💚 Cashback Tracking — Track expected vs credited cashback per transaction
• 🎯 Cashback Cap Monitoring — Monthly/Quarterly/Annual cap tracking with reset alerts
• 👥 Money Owed Tracking — Track when friends/family owe you money from shared expenses
• 💰 Repayment Tracking — Full partial payment history with person-wise summaries
• 🎫 Annual Fee Tracking — Monitor fee waiver progress and renewal dates
• 📊 Smart Dashboard — Unified view of all financial alerts and summaries

• ✅ Passwords hashed with bcrypt (12 rounds)
• ✅ JWT-secured sessions via NextAuth
• ✅ Only last 4 card digits stored — no full card numbers, CVV, or sensitive data
• ✅ All API routes are authenticated
• ✅ Server-side input validation with Zod
• ✅ CSRF protection via NextAuth
• ✅ SQL injection protection via Prisma ORM

• Node.js 20+
• Docker (for local PostgreSQL)

git clone https://github.com/yourusername/cardzen
cd cardzen
npm install

cp .env.example .env

Edit .env:

# Option A: Use local Docker DB
DATABASE_URL="postgresql://cardzen:cardzen_dev@localhost:5432/cardzen"

# Option B: Use Neon (recommended for production)
DATABASE_URL="postgresql://username:password@ep-xxxx.us-east-2.aws.neon.tech/cardzen?sslmode=require"

NEXTAUTH_SECRET="generate-with: openssl rand -base64 32"
NEXTAUTH_URL="http://localhost:3000"
APP_ENV="development"
NEXT_PUBLIC_APP_URL="http://localhost:3000"
NEXT_PUBLIC_REGISTRATION_ENABLED=false
# Make the above variable true to enable user registration feature from the login page

docker-compose -f docker-compose.dev.yml up -d

npx prisma migrate dev --name init
npx prisma generate

npm run dev

Open http://localhost:3000 and register your account.

Neon provides serverless PostgreSQL — perfect for this app.

1. Create a free account at neon.tech
2. Create a new project called "cardzen"
3. Copy the connection string from the dashboard
4. Set it as DATABASE_URL in your .env
5. Run npx prisma migrate deploy

cp .env.example .env
# Edit .env with production values

Required environment variables:

DATABASE_URL="your-neon-or-postgres-url"
NEXTAUTH_SECRET="super-secret-min-32-chars"
NEXTAUTH_URL="https://yourdomain.com"
APP_ENV="production"
NEXT_PUBLIC_APP_URL="http://localhost:3000"
NEXT_PUBLIC_REGISTRATION_ENABLED=false

If using bundled PostgreSQL (docker-compose.yml):

POSTGRES_USER=cardzen
POSTGRES_PASSWORD=your_strong_password

docker-compose up -d --build

docker-compose exec app npx prisma migrate deploy

Open http://your-server:3000 in your browser.

User
├── CreditCard (many)
│   ├── Transaction (many)
│   │   ├── BorrowedExpense (one)
│   │   │   └── RepaymentRecord (many)
│   │   └── CashbackRecord (one)
│   ├── BillingCycle (many)
│   │   └── Transaction (many)
│   └── CashbackRecord (many)

src/
├── app/
│   ├── (auth)/              # Login & Register pages
│   │   ├── login/
│   │   └── register/
│   ├── (dashboard)/         # Protected app pages
│   │   ├── dashboard/       # Main overview
│   │   ├── cards/           # Card management
│   │   ├── transactions/    # Expense tracking
│   │   ├── cashback/        # Cashback tracking
│   │   ├── borrowed/        # Money owed tracking
│   │   ├── annual-fee/      # Annual fee tracking
│   │   ├── billing/         # Billing cycles
│   │   └── settings/
│   └── api/                 # REST API routes
│       ├── auth/
│       ├── cards/
│       ├── transactions/
│       ├── cashback/
│       ├── borrowed/
│       ├── billing/
│       └── dashboard/
├── components/
│   ├── layout/              # Sidebar, TopBar
│   ├── cards/               # Card components
│   ├── transactions/        # Transaction components
│   ├── cashback/            # Cashback components
│   ├── borrowed/            # Borrowed expense components
│   ├── billing/             # Billing components
│   └── ui/                  # Base UI components
├── lib/
│   ├── auth.ts              # NextAuth config
│   ├── db.ts                # Prisma client
│   └── utils.ts             # Utilities
├── hooks/
│   └── use-toast.ts
├── types/
│   └── index.ts
└── middleware.ts
prisma/
└── schema.prisma

openssl rand -base64 32

MIT — Use freely for personal projects.