An intelligent car financing and leasing recommendation platform that uses OpenAI's API with web search to provide personalized Toyota vehicle recommendations based on your financial profile and lifestyle needs.

• AI-Powered Analysis: Uses OpenAI's GPT-4o with web search to find the best Toyota vehicles for your budget
• Real-Time Data: Fetches current pricing, APR rates, and lease terms from toyota.com and kbb.com
• Three Tier System: Get personalized recommendations across Budget, Balanced, and Premium categories

• Dynamic Finance Calculator: Adjust down payment and loan term with real-time monthly payment updates
• Lease Calculator: Customize lease terms and annual mileage with instant payment adjustments
• Live Calculations: Uses actual loan amortization formulas for accurate estimates

• 10-Question Assessment: Comprehensive financial and lifestyle analysis
• Smart Recommendations: Based on:
  • Income and expenses
  • Credit score range
  • Ownership horizon
  • Annual mileage
  • Passenger needs
  • Commute profile

• Modern Design: Clean, Toyota-branded interface with smooth animations
• Responsive: Works seamlessly on desktop, tablet, and mobile
• Interactive Sliders: Real-time adjustment of financial parameters
• Image Carousel: Multiple views for each recommended vehicle

• React 18.3 - UI library
• TypeScript - Type safety
• Vite - Fast build tool
• Tailwind CSS - Utility-first styling
• Framer Motion - Smooth animations
• Radix UI - Accessible component primitives
• React Router - Client-side routing

• Node.js 20+ - Runtime environment
• Express.js - Web framework
• TypeScript - Type safety
• OpenAI API - AI recommendations with web search
• CORS - Cross-origin resource sharing
• dotenv - Environment variable management

Before you begin, ensure you have the following installed:

• Node.js (v20 or higher) - Download
• npm (comes with Node.js)
• OpenAI API Key - Get one here

git clone https://github.com/yourusername/Toyota-Financing.git
cd Toyota-Financing

cd frontend
npm install

cd ../backend
npm install

Create a .env file in the backend directory:

cd backend
touch .env

Add your OpenAI API key to .env:

OPENAI_API_KEY=your-actual-openai-api-key-here

⚠️ Important: Never commit your .env file to version control. It's already in .gitignore.

You'll need two terminal windows - one for frontend, one for backend.

cd backend
npm run dev

The backend will start on http://localhost:3000

cd frontend
npm run dev

The frontend will start on http://localhost:5173

cd frontend
npm run build

cd backend
npm run build

Toyota-Financing/
├── frontend/                 # React frontend application
│   ├── src/
│   │   ├── App.tsx          # Main application component
│   │   ├── main.tsx         # Application entry point
│   │   ├── index.css        # Global styles
│   │   └── components/      # Reusable UI components
│   │       └── ui/          # Radix UI components
│   ├── public/              # Static assets
│   ├── package.json         # Frontend dependencies
│   └── vite.config.ts       # Vite configuration
│
├── backend/                 # Express backend server
│   ├── src/
│   │   └── index.ts         # Main server file with OpenAI integration
│   ├── package.json         # Backend dependencies
│   ├── tsconfig.json        # TypeScript configuration
│   └── .env                 # Environment variables (create this!)
│
├── .gitignore              # Git ignore rules
└── README.md               # This file

User fills questionnaire → Backend sends to OpenAI → AI searches web for data → 
Returns 3 vehicle recommendations → Frontend displays with interactive calculators

• Uses OpenAI Responses API with gpt-4o model
• Web Search Tool: Searches toyota.com and kbb.com for real-time data
• Structured Output: Returns JSON with vehicle specs, pricing, and financing terms

payment = (loanAmount × monthlyRate × (1 + monthlyRate)^months) / 
          ((1 + monthlyRate)^months - 1)

adjustedPayment = basePayment × mileageMultiplier × termMultiplier

• Mileage: +3% per 2,500 miles over 12,000/year base
• Term: ±1-1.5% per 6 months from 36-month base

Generates personalized vehicle recommendations based on user financial profile.

Request Body:

{
  "gross_monthly_income": 4000,
  "other_monthly_income": 2000,
  "fixed_monthly_expenses": 1000,
  "liquid_savings": 10000,
  "credit_score": "580-669 (Fair)",
  "ownership_horizon": "5-6 years",
  "annual_mileage": "10,000-15,000",
  "passenger_needs": "2-3 people",
  "commute_profile": "City driving",
  "down_payment": 100
}

Response:

{
  "Budget": {
    "year": 2025,
    "make": "Toyota",
    "model": "Corolla",
    "trim": "LE",
    "price": 23460,
    "mileage": "35 MPG combined",
    "seats": 5,
    "headline_feature": "Compact efficiency",
    "finance": {
      "apr_percent": 5.99,
      "term_months": 60,
      "estimated_monthly_payment": 451
    },
    "lease": {
      "term_months": 36,
      "estimated_monthly_payment": 269,
      "annual_mileage_limit": 10000,
      "lease_score": 75
    }
  },
  "Balanced": { /* ... */ },
  "Premium": { /* ... */ },
  "Affordability": { /* ... */ },
  "Recommendation": { /* ... */ }
}

OpenAIError: Missing credentials. Please pass an apiKey...

Solution: Ensure .env file exists in backend/ directory with valid OPENAI_API_KEY

Solution: Use tsx instead of ts-node:

npm run dev  # This uses tsx

Solution: Kill the process using port 3000:

# macOS/Linux
lsof -ti:3000 | xargs kill -9

# Windows
netstat -ano | findstr :3000
taskkill /PID <PID> /F

Solution:

1. Check backend terminal for error messages
2. Verify backend is running on port 3000
3. Ensure OpenAI API key is valid

Solution: Backend already has CORS enabled. If issues persist:

1. Clear browser cache
2. Restart both frontend and backend servers

Solution:

• Check that you're using gpt-4o (not gpt-4.1 or other invalid models)
• Verify your OpenAI account has API access enabled

Solution:

• Wait a few moments and try again
• Check your OpenAI usage limits at platform.openai.com

1. Credit Score Impact: Better credit scores result in lower APR recommendations
2. Down Payment: Higher down payments significantly reduce monthly payments
3. Lease vs Finance: Leasing typically offers lower monthly payments but no ownership
4. Mileage Consideration: High annual mileage makes financing more economical than leasing
5. Term Length: Longer terms = lower monthly payments but more total interest

• Never commit .env files to version control
• API keys should be kept secret and rotated regularly
• Backend validation sanitizes all user inputs
• HTTPS recommended for production deployments

1. Build: npm run build
2. Deploy dist/ directory
3. Set environment variable for API URL if needed

1. Ensure package.json has start script
2. Set OPENAI_API_KEY environment variable
3. Deploy from GitHub or via CLI

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

This project is licensed under the MIT License - see the LICENSE file for details.

Amogh Sood

• OpenAI - AI recommendations with web search
• Toyota - Vehicle data source
• Kelley Blue Book - Pricing and specifications
• Radix UI - Accessible component primitives
• Framer Motion - Animation library

If you encounter any issues or have questions:

1. Check the Troubleshooting section
2. Review existing GitHub issues
3. Create a new issue with detailed information

Made with ❤️ for Toyota enthusiasts