A full-stack (MERN) Note-taking application built with React (frontend), Node.js + Express (backend), and MongoDB (database).

This README explains how the application works, its architecture, prerequisites, required environment variables, and how to run both the frontend and backend locally for development.

/
├── backend/           # Express API (Node.js)
│   ├── models/        # Mongoose models
│   ├── routes/        # Express routes
│   ├── controllers/   # Route handlers / logic
│   ├── .env.example   # Example environment variables
│   └── server.js      # Main entry point for backend
├── frontend/          # React application
│   ├── public/
│   ├── src/
│   └── package.json
└── README.md

• Location: frontend/
• Built with React (JavaScript), providing a responsive and interactive UI for note-taking.
• Communicates with the backend via HTTP requests (usually to /api/notes, /api/users, etc).
• Handles user authentication (login/signup), note creation, editing, deletion, and visualization.

• Location: backend/
• RESTful API built with Node.js and Express.
• Handles user authentication, CRUD operations for notes, and connects to MongoDB.
• Uses environment variables for sensitive data (MongoDB URI, JWT secret, etc).
• Has error handling and input validation for reliability and security.

• Stores users and notes.
• Accessed by the backend via Mongoose ODM.

• Node.js (v18 or higher recommended)
• npm (comes with Node.js)
• MongoDB Atlas account or local MongoDB server

Create a .env file in the backend/ directory.
You can copy .env.example as a template:

cp backend/.env.example backend/.env

Required variables:

PORT=5000                           # Backend server port
MONGODB_URI=mongodb+srv://...       # Your MongoDB connection string
JWT_SECRET=your_jwt_secret          # Secret key for JWT signing

Note: Never commit your real .env to version control.

cd backend
npm install

cd ../frontend
npm install

• If using Atlas: ensure your cluster is running.
• If using local MongoDB: make sure mongod is running.

cd backend
npm run dev

• Backend API will run at http://localhost:5000

cd ../frontend
npm start

• React app will run at http://localhost:3000 and proxy API requests to the backend.

• Make sure the proxy field in frontend/package.json is set to the backend URL (usually "proxy": "http://localhost:5000").
• If you change ports or API paths, update them in both frontend and backend accordingly.
• The backend uses JWT for authentication. Make sure your JWT_SECRET is strong and private.
• CORS is enabled for frontend-backend communication during development.

• Test user signup, login, note creation, editing, and deletion.
• Check network requests in browser dev tools for error messages.
• Backend logs errors to the console.

• For production, build the frontend and serve static files from Express, or deploy frontend and backend separately (e.g., Vercel/Netlify + Render/Heroku).
• Set environment variables in your cloud environment.

Q: What if I get MongoDB connection errors?
A: Check your MONGODB_URI in .env and ensure your IP is whitelisted in Atlas.

Q: How do I reset my notes/users?
A: Drop the relevant collections in your MongoDB database.

MIT

Enjoy fast, secure, and reliable note-taking!