🎯 BidZo - Full-Stack Monorepo

A production-ready monorepo structure for full-stack web applications with separated frontend and backend, enabling independent development and deployment.

An auction marketplace where users can list items and place bids. Features include authentication, listings, bidding, wallet, and order tracking with an escrow-based payment system.

📋 Table of Contents

• Project Overview
• Folder Structure
• Tech Stack
• Quick Start
• Development Commands
• Project Structure
• API Documentation
• Environment Configuration
• Troubleshooting
• Future Enhancements

---

🚀 Project Overview

BidZo is a scalable monorepo setup that provides:

• Frontend: React application with Vite for fast development
• Backend: Express.js REST API server
• Shared: Reusable utilities, types, and constants
• Concurrent Development: Run both apps simultaneously with a single command

Features

✅ Production-Ready Structure - Clean separation of concerns
✅ Hot Module Reloading - Fast development experience
✅ Concurrent Execution - Run frontend and backend together
✅ Independent Scaling - Scale apps independently
✅ Shared Code - Reusable utilities across the monorepo
✅ Environment Configuration - Separate config per app
✅ CORS Enabled - Frontend-backend communication ready

---

📁 Folder Structure

BidZo/
├── client/                    # React + Vite frontend
│   ├── src/
│   │   ├── components/       # Reusable React components
│   │   ├── pages/            # Page components
│   │   ├── App.jsx           # Root component
│   │   ├── App.css           # App styles
│   │   ├── main.jsx          # Entry point
│   │   └── index.css         # Global styles
│   ├── public/               # Static assets
│   ├── index.html            # HTML entry point
│   ├── vite.config.js        # Vite configuration
│   ├── package.json          # Client dependencies
│   ├── .env.example          # Environment variables template
│   ├── .env.local            # Local environment variables
│   └── .gitignore
│
├── server/                    # Express.js backend
│   ├── index.js              # Main server file
│   ├── package.json          # Server dependencies
│   ├── .env.example          # Environment variables template
│   ├── .env                  # Environment variables
│   └── .gitignore
│
├── shared/                    # Shared code (client & server)
│   ├── types/
│   │   ├── api.ts           # API types
│   │   └── README.md
│   ├── utils/
│   │   ├── validators.js    # Validation utilities
│   │   └── README.md
│   ├── constants/
│   │   ├── index.js         # Shared constants
│   │   └── README.md
│   ├── README.md
│   └── .gitignore
│
├── package.json              # Root monorepo config
├── .gitignore                # Git ignore rules
└── README.md                 # This file

---

🛠 Tech Stack

Layer	Technology	Version	Purpose
Frontend	React	18.2+	UI library
	Vite	5.0+	Build tool & dev server
	Axios	1.6+	HTTP client
Backend	Express.js	4.18+	Web framework
	Node.js	18.0+	Runtime
	CORS	2.8+	Cross-origin requests
	dotenv	16.3+	Environment variables
Dev Tools	concurrently	8.2+	Run multiple commands
	nodemon	3.0+	Auto-restart server

---

⚡ Quick Start

Prerequisites

• Node.js >= 18.0.0
• npm >= 9.0.0
• Git (for version control)

Installation

1. Clone or navigate to the repository

   cd BidZo

2. Install all dependencies

   npm run install-all

   This command installs:

   • Root dependencies (concurrently)
   • Client dependencies (React, Vite, etc.)
   • Server dependencies (Express, dotenv, etc.)

3. Start development servers

   npm run dev

4. Access the application

   • 🌐 Frontend: http://localhost:3000
   • 🔌 Backend: http://localhost:5000
   • 💚 Health Check: http://localhost:5000/health

---

📜 Development Commands

Root Level Commands

# Run both client and server concurrently
npm run dev

# Run only the frontend
npm run client

# Run only the backend
npm run server

# Install all dependencies
npm run install-all

# Build for production
npm run build

# Build only frontend
npm run build:client

# Build only backend
npm run build:server

Client Commands (from /client)

# Development server with hot reload
npm run dev

# Build for production
npm run build

# Preview production build
npm run preview

# Lint code
npm run lint

Server Commands (from /server)

# Start server
npm start

# Start with nodemon (auto-restart on changes)
npm run dev

# Run tests
npm test

---

🏗 Project Structure (Detailed)

Frontend Structure (/client)

The React frontend is built with Vite for fast development and optimized production builds.

Config Files:

• vite.config.js - Vite configuration with React plugin
• index.html - HTML entry point
• .env.example - Environment variables template
• .env.local - Local development variables

Source Files:

• src/main.jsx - React DOM render entry point
• src/App.jsx - Root component with health check
• src/App.css - Component styles
• src/index.css - Global styles
• src/components/ - Reusable React components
• src/pages/ - Page-level components

Features:

• Server health status indicator
• Sample counter component
• Beautiful gradient UI
• Mobile-responsive design

Backend Structure (/server)

The Express server provides REST API endpoints and is configured with CORS for frontend communication.

Config Files:

• .env - Environment variables (PORT, NODE_ENV, etc.)
• .env.example - Template for environment setup
• package.json - Dependencies and scripts

API Routes:

Method	Endpoint	Description
GET	/health	Server health check
GET	/api/info	Server information
POST	/api/message	Accept and echo messages

Features:

• CORS middleware for frontend requests
• JSON request/response handling
• Error handling middleware
• 404 handler
• Logging on server start

Shared Code (/shared)

Reusable code for both client and server.

Types (/types):

• api.ts - API response and model types
• TypeScript interfaces for type safety

Utilities (/utils):

• validators.js - Input validation functions
• Email, URL, and sanitization helpers

Constants (/constants):

• index.js - API endpoints, HTTP status codes, error messages

---

🔌 API Documentation

Health Check

Endpoint: GET /health

Description: Verify server is running

Response:

{
  "status": "ok",
  "timestamp": "2026-04-08T12:00:00.000Z",
  "message": "Server is running successfully"
}

Server Info

Endpoint: GET /api/info

Description: Get server metadata

Response:

{
  "app": "BidZo Backend",
  "version": "1.0.0",
  "environment": "development"
}

Post Message

Endpoint: POST /api/message

Description: Send a message to the server

Request Body:

{
  "message": "Hello, Server!"
}

Response:

{
  "success": true,
  "receivedMessage": "Hello, Server!",
  "timestamp": "2026-04-08T12:00:00.000Z"
}

---

⚙️ Environment Configuration

Client Environment (.env.local)

# API URL for backend communication
VITE_API_URL=http://localhost:5000

Server Environment (.env)

# Application environment
NODE_ENV=development

# Server port
PORT=5000

# API and client URLs
API_URL=http://localhost:5000
CLIENT_URL=http://localhost:3000

How to use:

1. Copy .env.example to .env.local (client) or .env (server)
2. Adjust values as needed
3. Server automatically loads from .env via dotenv
4. Client uses VITE_ prefix for Vite build access

---

🐛 Troubleshooting

Port Already in Use

Problem: Error: listen EADDRINUSE :::5000

Solution:

# Kill process using port 5000
lsof -ti:5000 | xargs kill -9

# Or change port in .env
PORT=5001

CORS Errors

Problem: Access to XMLHttpRequest blocked by CORS policy

Solution:

• Ensure server is running on port 5000
• Check .env files have correct URLs
• Verify CORS middleware in server/index.js

Modules Not Found

Problem: Cannot find module 'express'

Solution:

# Reinstall dependencies
npm run install-all

# Or in specific folder
cd server && npm install
cd ../client && npm install

Port 3000 Already in Use

Problem: Error: EADDRINUSE: address already in use :::3000

Solution:

# Kill process using port 3000
lsof -ti:3000 | xargs kill -9

# Or edit vite.config.js to use different port

Frontend Can't Connect to Backend

Problem: Health check shows "offline"

Solution:

1. Verify server is running: npm run server
2. Check CORS configuration in server/index.js
3. Ensure VITE_API_URL matches server URL
4. Check browser console for specific errors

---

📦 Dependency Management

Adding Dependencies

Client:

cd client
npm install axios

Server:

cd server
npm install next-middleware

Updating Dependencies

All packages:

npm run install-all

---

🚀 Deployment Checklist

• Update .env.example files with production values
• Create .env.production files
• Build frontend: npm run build:client
• Build backend: npm run build:server
• Test production builds locally
• Configure CI/CD pipeline
• Set up environment variables on hosting platform
• Deploy to staging environment first
• Run smoke tests on staging
• Deploy to production

---

🔮 Future Enhancements

Phase 1: Core Features

• Database integration (MongoDB/PostgreSQL)
• Authentication system (JWT/OAuth)
• API documentation (Swagger/OpenAPI)
• Unit and integration tests
• Error logging and monitoring

Phase 2: Advanced Features

• WebSocket support for real-time features
• Caching layer (Redis)
• Rate limiting
• Input validation and sanitization
• GraphQL API alternative

Phase 3: DevOps & Deployment

• Docker containerization
• Kubernetes orchestration
• GitHub Actions CI/CD
• Automated testing in pipeline
• Staging and production environments

Phase 4: Optimization

• Performance monitoring
• Analytics integration
• SEO optimization
• Code splitting and lazy loading
• Progressive Web App (PWA) features

---

📚 Resources

• React Documentation
• Vite Documentation
• Express.js Documentation
• Node.js Best Practices

---

🤝 Contributing

1. Create a feature branch: git checkout -b feature/amazing-feature
2. Commit your changes: git commit -m 'Add amazing feature'
3. Push to branch: git push origin feature/amazing-feature
4. Open a Pull Request

---

📝 License

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

---

🎉 Getting Help

• Check the Troubleshooting section
• Review error messages in browser console
• Check server logs in terminal
• Create an issue on GitHub

---

Happy coding! 🚀

Last updated: April 8, 2026