Building a Decentralized Course Marketplace on Ethereum

🚀 ETH Course Marketplace

A comprehensive exploration of blockchain technology, smart contracts, and modern web development

Next.js Solidity Web3.js Ethereum MetaMask

🎯 Project Overview

For my bachelor's degree final project, I developed ETH Course Marketplace - a fully decentralized platform where users can purchase, manage, and access online courses using Ethereum blockchain technology. This project represents the intersection of modern web development, blockchain technology, and user experience design.

🔗 Full-Stack Web3

Complete dApp Development

⛽ Gas Optimized

Efficient Smart Contracts

🌍 Multilingual

Global Accessibility

📱 Responsive

Mobile-First Design

🏗️ Technical Architecture

Frontend Stack

Next.js 12.3.4 - React framework for production-ready applications
React 18.2.0 - Modern component-based UI development
Tailwind CSS 3.1.7 - Utility-first CSS framework
SWR 1.3.0 - Data fetching library for efficient state management
Web3.js 1.7.5 - Ethereum blockchain interaction

Blockchain Stack

Solidity - Smart contract development language
Truffle Suite - Development framework for Ethereum dApps
MetaMask - Browser wallet integration
Ethereum Network - Decentralized blockchain platform

⚙️ Core Features Implementation

🔐 Smart Contract Architecture

The heart of the application is the CourseMarketplace.sol contract implementing state management, ownership verification, and secure transactions.

enum State {
    Purchased,
    Activated, 
    Deactivated
}

struct Course {
    uint id;
    uint price;
    bytes32 proof;
    address owner;
    State state;
}

🌐 Web3 Integration Layer

Sophisticated Web3 provider system handling wallet connections, network management, and blockchain state synchronization.

const createWeb3State = ({ 
    web3, provider, contract, isLoading 
}) => {
  return {
    web3, provider, contract, isLoading,
    hooks: setupHooks({ web3, provider, contract }),
  };
};

🎨 User Interface Components

Component-based architecture with responsive design, interactive modals, and real-time transaction status updates.

• Course catalog with filtering
• Wallet connection interface
• Purchase confirmation modals
• Course management dashboard

🧪 Testing & Quality Assurance

Comprehensive testing strategy covering smart contracts, purchase flows, access control, and error handling scenarios.

describe("Purchase the new course", () => {
  it("should not allow repurchase", async () => {
    await catchRevert(
      _contract.purchaseCourse(courseId, proof, {
        from: buyer, value
      })
    );
  });
});

💡 Technical Challenges & Solutions

Challenge 1: Gas Optimization

Problem: High transaction costs affecting user adoption

Solution:

Implemented custom errors instead of require statements
Optimized storage patterns in smart contracts
Batch operations where possible

Challenge 2: Wallet Integration

Problem: Complex MetaMask connection and network switching