AI Chatbot Application

A full-stack chatbot application with AI capabilities powered by OpenAI. This project offers multiple implementation options to suit different needs:

• NestJS + React (Vite) - The original implementation
• FastAPI + React (Vite) - Python backend alternative
• NestJS + Next.js - Enhanced frontend with SSR capabilities

🚀 Quick Start

Prerequisites

• Node.js 18+
• MongoDB 6.0+
• OpenAI API Key

Setup Steps

This project offers multiple tech stack options. Follow the instructions for your preferred combination:

1. Install Backend Dependencies

cd backend
npm install

2. Configure Backend Environment

Create backend/.env:

MONGODB_URI=mongodb://localhost:27017/chatbot
OPENAI_API_KEY=your_openai_api_key
PORT=3000
NODE_ENV=development

3. Setup MongoDB

# Install MongoDB (macOS)
brew tap mongodb/brew
brew install mongodb-community@7.0
brew services start mongodb-community@7.0

# Verify MongoDB is running
mongosh --eval "db.adminCommand('ping')"

The database and collection will be created automatically when you run the application.

4. Start Backend

cd backend
npm run start:dev

5. Install Frontend Dependencies

cd ../frontend
npm install

6. Start Frontend

npm run dev

7. Open Application

Navigate to http://localhost:5173 in your browser

📚 Documentation

For detailed setup instructions, see SETUP.md

Sub-project Documentation

• FastAPI Backend README
• Next.js Frontend README

🏗️ Project Structure

interviewProjects/
├── backend/              # NestJS backend
│   ├── src/
│   │   ├── chatbot/     # Chatbot module
│   │   ├── main.ts      # Entry point
│   │   └── app.module.ts
│   └── package.json
├── backend-fastapi/      # FastAPI backend (Python)
│   ├── app/
│   │   ├── main.py       # Application entry point
│   │   ├── chatbot/      # Chatbot module
│   │   ├── database/     # Database connection
│   │   ├── models/       # Database models
│   │   ├── schemas/      # Pydantic schemas
│   │   └── utils/        # Utility functions
│   ├── requirements.txt  # Python dependencies
│   └── README.md         # FastAPI backend documentation
├── frontend/             # React frontend (Vite)
│   ├── src/
│   │   ├── components/  # UI components
│   │   ├── pages/       # Page components
│   │   └── App.tsx
│   └── package.json
├── frontend-nextjs/      # Next.js frontend
│   ├── app/              # Next.js App Router
│   ├── components/       # React components
│   ├── next.config.js    # Next.js configuration
│   └── README.md         # Next.js frontend documentation
├── database/
│   └── mongodb-setup.md # MongoDB setup guide
├── SETUP.md             # Detailed setup guide
└── README.md            # This file

✨ Features

• 🤖 AI-powered chatbot using OpenAI GPT-3.5
• 💬 Real-time conversation interface
• 💾 Persistent chat history in MongoDB
• 🎨 Modern, responsive UI with animations
• 🌙 Dark/Light mode support
• 🔒 Type-safe with TypeScript
• ⚡ Fast development with multiple frameworks (Vite, Next.js)
• 🏗️ Scalable architecture with multiple backend options (NestJS, FastAPI)
• 📊 Flexible NoSQL document storage

🛠️ Technology Stack

Backend Options

NestJS (Node.js)

• NestJS - Progressive Node.js framework
• TypeScript - Type-safe JavaScript
• Mongoose - MongoDB ODM
• MongoDB - NoSQL document database
• OpenAI API - AI capabilities

FastAPI (Python)

• FastAPI - High-performance Python web framework
• Python 3.8+ - Modern Python runtime
• Motor - Asynchronous MongoDB driver
• Pydantic v2 - Data validation using Python type hints
• Uvicorn - Lightning-fast ASGI server

Frontend Options

React + Vite (SPA)

• React 18 - UI library
• TypeScript - Type-safe JavaScript
• Vite - Build tool
• Axios - HTTP client
• CSS3 - Modern styling

Next.js (SSR)

• Next.js 14 - The React Framework for the Web
• App Router - File-system based routing
• Server Components - Improved performance and bundle size
• SSR - Server-Side Rendering for better SEO
• Hybrid Rendering - Mix of static and dynamic content

📡 API Endpoints

• GET /chatbot/health - Health check
• POST /chatbot/message - Send message to chatbot
• GET /chatbot/history/:conversationId - Get conversation history

🔧 Development

Backend Commands

cd backend
npm run start:dev    # Development mode
npm run build        # Build for production
npm run lint         # Lint code

Frontend Commands

cd frontend
npm run dev          # Development mode
npm run build        # Build for production
npm run preview      # Preview production build

📝 License

MIT

🤝 Contributing

Feel free to submit issues and enhancement requests!

📧 Support

For questions and support, please refer to SETUP.md for troubleshooting tips.