🦊 Login with MetaMask

A simple full-stack demo showing how to implement MetaMask authentication in a web application. This project demonstrates how to connect a dApp to the Ethereum blockchain, verify wallet ownership, and log users in securely without traditional credentials.

📂 Project Structure

The repository has two main parts:

• backend → REST API built with Express.js

• frontend → Web client built with Next.js

🚀 Getting Started

1. Install Dependencies

From the root of the repo:

yarn install                 # Install root dependencies
cd backend && yarn install   # Install backend dependencies
cd ../frontend && yarn install  # Install frontend dependencies
cd ..                        # Return to root

2. Start the Project

Run both frontend and backend together:

yarn start

• Backend → runs at http://localhost:8000

• Frontend → runs at http://localhost:3000

3. Run Services Separately (Optional)

You can also start each service individually:

# Start backend
cd backend
yarn start

# Start frontend
cd frontend
yarn start

🔑 Features

• 🔒 Secure wallet-based authentication using MetaMask

• 🌐 Full-stack setup with Next.js and Express.js

• 🛠️ Easy to run locally with yarn start

🔄 Usage Flow

sequenceDiagram
    participant U as User (Browser + MetaMask)
    participant F as Frontend (Next.js)
    participant B as Backend (Express API)

    U->>F: Open dApp (login page)
    F->>U: Request wallet connection
    U->>MetaMask: Sign message with private key
    MetaMask->>F: Return signed message
    F->>B: Send signed message + wallet address
    B->>B: Verify signature & generate auth token
    B->>F: Return success + session token
    F->>U: User logged in (authenticated)