LangGraph Booking Agent

LangGraph AI travel agent with 15+ tools for flight, hotel, car, and excursion booking using Google AI.

A sophisticated full-stack travel booking system that combines the power of LangGraph, Google Generative AI, and modern web technologies to provide an intelligent conversational interface for comprehensive travel management.

🚀 Quick Start

Prerequisites

• Python 3.8+ for backend
• Node.js 18+ for frontend
• API Keys: Google AI, Groq, Tavily, LangSmith

Environment Setup

1. Clone the repository

   git clone <repository-url>
   cd LangGraph-Booking-Agent

2. Backend Setup

   cd backend
   pip install -r requirements.txt
   cp env.yaml.template env.yaml
   # Edit env.yaml with your API keys

3. Frontend Setup

   cd frontend
   npm install
   cp .env.local.example .env.local
   # Edit .env.local with your backend URL

4. Start the System

   # Terminal 1: Backend
   cd backend
   python app.py
   
   # Terminal 2: Frontend
   cd frontend
   npm run dev

5. Access the Application

   • Frontend: http://localhost:3000
   • Backend API: http://localhost:8000

🏗️ Architecture Overview

LangGraph Booking Agent
├── backend/                 # LangGraph AI Backend
│   ├── app.py              # Main LangGraph application
│   ├── agent_service.py    # FastAPI service wrapper
│   ├── database.py         # Database utilities
│   └── requirements.txt    # Python dependencies
├── frontend/               # React Frontend
│   ├── src/
│   │   ├── components/     # React components
│   │   ├── contexts/       # State management
│   │   ├── services/       # API communication
│   │   └── types/          # TypeScript definitions
│   └── package.json        # Node.js dependencies
└── README.md              # This file

🧠 Backend: LangGraph AI Engine

Core Technologies

• LangGraph: Stateful conversation management
• Google Generative AI: Gemini 2.5 Flash for chat completions
• Custom Vector Store: Semantic policy lookup
• SQLite Database: Travel data with automatic date sync
• FastAPI: RESTful API service

Key Features

• 18+ Specialized Tools: Flight, hotel, car rental, excursion management
• Stateful Conversations: Persistent memory across sessions
• Real-time Data Sync: Automatic timezone-aware updates
• Error Recovery: Graceful fallbacks and retry mechanisms
• Business Logic Validation: Ticket ownership, booking rules

Database Schema

• 8 Main Tables: flights, tickets, hotels, car_rentals, trip_recommendations
• Hosted: Google Cloud Storage with local caching
• Auto-updates: Flight dates synchronized to current time

🎨 Frontend: Modern React Interface

Core Technologies

• Next.js 15: React framework with App Router
• TypeScript: Type-safe development
• Tailwind CSS 4: Utility-first styling
• React Context: State management
• Axios: HTTP client with retry logic

Key Features

• Glass Morphism UI: Modern, futuristic design
• Real-time Chat: Streaming message updates
• Responsive Design: Mobile-first approach
• Suggested Questions: Quick-start interactions
• Thread Persistence: Conversation history across sessions

🔧 Configuration

Backend Environment Variables

# env.yaml
GROQ_API_KEY: your_groq_api_key
GOOGLE_API_KEY: your_google_api_key
TAVILY_API_KEY: your_tavily_api_key
LANGSMITH_API_KEY: your_langsmith_api_key
LANGSMITH_TRACING: true
LANGSMITH_ENDPOINT: https://api.smith.langchain.com
LANGSMITH_PROJECT: Booking-Agent-LC

Frontend Environment Variables

# .env.local
NEXT_PUBLIC_API_URL=http://localhost:8000

🛠️ Available Tools

Flight Management (4 tools)

• fetch_user_flight_information - Get user's flight details
• search_flights - Search available flights
• update_ticket_to_new_flight - Change flight bookings
• cancel_ticket - Cancel flight tickets

Hotel Management (4 tools)

• search_hotels - Find available hotels
• book_hotel - Reserve hotel rooms
• update_hotel - Modify hotel bookings
• cancel_hotel - Cancel hotel reservations

Car Rental Management (4 tools)

• search_car_rentals - Find car rental options
• book_car_rental - Reserve vehicles
• update_car_rental - Modify rental details
• cancel_car_rental - Cancel car rentals

Trip Recommendations (4 tools)

• search_trip_recommendations - Find excursions and activities
• book_excursion - Reserve excursions
• update_excursion - Modify excursion details
• cancel_excursion - Cancel excursions

Information & Policy (2 tools)

• lookup_policy - Semantic search through company policies
• TavilySearch - Real-time web search for current information

🚀 Deployment

Backend Deployment (Google Cloud Run)

cd backend
gcloud run deploy travel-agent-backend \
  --source . \
  --platform managed \
  --region us-central1 \
  --allow-unauthenticated

Frontend Deployment (Netlify)

cd frontend
npm run build
# Deploy the 'out' directory to Netlify

🧪 Testing

Backend Testing

cd backend
python -m pytest tests/

Frontend Testing

cd frontend
npm test
npm run test:coverage

📊 Performance

Backend Optimizations

• Lazy Loading: Database and retriever initialization
• Caching: Embeddings and database queries
• Streaming: Real-time response streaming
• Error Recovery: Automatic retry mechanisms

Frontend Optimizations

• Code Splitting: Next.js automatic optimization
• Bundle Optimization: Tree shaking and CSS purging
• Caching: Local storage and service workers
• Responsive Images: Next.js image optimization

🔒 Security

Backend Security

• Input Validation: SQL injection prevention
• Authentication: Passenger ID verification
• API Key Protection: Environment variable security
• Business Logic: Booking rule enforcement

Frontend Security

• TypeScript: Type safety and validation
• HTTPS: Secure API communication
• Input Sanitization: XSS prevention
• Error Handling: Graceful error recovery

🐛 Troubleshooting

Common Issues

1. API Connection Failed

   • Verify backend is running on correct port
   • Check environment variables
   • Ensure CORS is properly configured

2. Database Issues

   • Check database URL accessibility
   • Verify SQLite file permissions
   • Monitor disk space for caching

3. Tool Execution Errors

   • Verify passenger ID configuration
   • Check API key validity
   • Review error logs for details

Debug Mode

# Backend
LANGSMITH_TRACING=true python app.py

# Frontend
NODE_ENV=development npm run dev

📈 Monitoring

LangSmith Integration

• Conversation Tracing: Full conversation flow
• Tool Execution: Performance monitoring
• Error Tracking: Automatic error reporting
• Analytics: Usage patterns and insights

Health Checks

• Backend: /health endpoint
• Frontend: Service availability monitoring
• Database: Connection status checks

🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Follow coding standards
   • TypeScript for frontend
   • Python type hints for backend
   • Comprehensive testing
4. Submit a pull request

Development Guidelines

• Write tests for new features
• Update documentation
• Follow existing code patterns
• Ensure responsive design
• Test across browsers

📄 License

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

🙏 Acknowledgments

• LangGraph Team: For the powerful conversation framework
• Google AI: For the Gemini model integration
• Next.js Team: For the excellent React framework
• Tailwind CSS: For the utility-first CSS framework

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Built with ❤️ using LangGraph, Google AI, and modern web technologies