LangDAO is a decentralized language exchange platform where users can instantly talk, teach, and earn with PyUSD, PayPal’s programmable stablecoin. It transforms traditional, centralized language learning into a borderless, peer-to-peer communication economy, removing banks, middlemen, and friction entirely. Tutors and learners connect directly using smart contracts that ensure instant, trustless PyUSD payments—no delays, no high fees, no bank accounts required.

Unlike platforms like italki or Baselang—where tutors are overbooked or locked behind costly subscriptions—LangDAO allows learners to start a real conversation with a native speaker instantly and pay only for the minutes they use. Built on blockchain, the system replaces bureaucracy with verifiable trust, while providing transparent micropayments that empower users globally.

All you need is a phone, an internet connection, and your voice. LangDAO unlocks earning potential for millions of native speakers—especially the global majority of unbanked or underemployed graduates—by turning language skills into income. By leveraging PyUSD’s instant, inclusive, programmable payments, LangDAO reimagines learning as both human connection and economic freedom.

I'll analyze the project structure and provide comprehensive technical details for your hackathon description. Let me examine the codebase to understand the full scope of the project.

[5 tools called]

Based on my comprehensive analysis of the LangDAO project, here are the technical details for your hackathon description:

LangDAO - Technical Project Details

🎯 Project Overview

LangDAO is a decentralized language learning platform that enables people worldwide to use their language skills to teach, learn, and earn crypto in Web3. The platform focuses on real-time video sessions with per-second billing, creating a sustainable economy for language education.

🏗️ Technical Architecture

Frontend Stack

• Framework: Next.js 15.2.3 with React 19
• Web3 Integration:
  • Wagmi 2.16.4 + Viem 2.34.0 for Ethereum interactions
  • RainbowKit 2.2.8 for wallet connection
  • Thirdweb 5.109.0 for additional Web3 functionality
• UI/UX: Tailwind CSS + DaisyUI for modern, responsive design
• State Management: Zustand for client-side state
• Real-time: Socket.io for live communication

Smart Contract Layer

• Language: Solidity ^0.8.0
• Network: Ethereum Sepolia Testnet
• Contract Address: 0x4Fb5675e6baE48C95c1D4f1b154E3d5e8E36112C
• Token: PYUSD (PayPal USD) for payments
• Key Features:
  • Per-second billing system
  • Multi-language support (38 languages)
  • Session lifecycle management
  • Automatic payment processing
  • Student/tutor registration system

WebRTC Video Infrastructure

• Technology: Custom WebRTC implementation
• Features:
  • Real-time video/audio communication
  • Session chat with timestamps
  • Cross-user status synchronization
  • Heartbeat monitoring (10-second intervals)
  • Professional UI with role badges
  • Multi-language support (16 languages)
• Deployment: Railway.app production environment
• Security: HTTPS/WSS protocols with automatic detection

Backend Services

• Architecture: Serverless/lightweight services
• WebSocket Server: Node.js for real-time signaling
• Event System: HTTP POST endpoints for session tracking
• Heartbeat Service: 10-second interval monitoring
• Integration: RESTful APIs for contract interactions

🔧 Core Technical Features

1. Smart Contract Functionality

// Key contract functions
- registerStudent(targetLanguage, budgetPerSec)
- registerTutor(languages[], ratePerSecond)
- depositFunds(amount) // PYUSD only
- startSession(tutorAddress, language)
- endSession(tutorAddress)
- hasSufficientBalance(student, tutor)

2. Real-time Payment System

• Per-second billing during active sessions
• Automatic session termination on disconnect
• PYUSD token integration for stable payments
• Balance validation before session start
• Refund system for unused funds

3. Multi-language Support

• 38 supported languages with ISO 639-1 codes
• Language-specific tutoring rates
• Student target language matching
• Tutor language capability verification

4. Session Management

• Session lifecycle tracking (start, active, end)
• Real-time cost calculation
• Automatic payment processing
• Session history and analytics
• Emergency session termination

🌐 Web3 Integration

Wallet Support

• MetaMask, WalletConnect, Coinbase Wallet
• Ledger, Rainbow Wallet, Safe Wallet
• Burner wallet for local development

Network Configuration

• Primary: Sepolia Testnet
• Development: Hardhat local network
• RPC: Alchemy integration with fallbacks

Token Economics

• Payment Token: PYUSD (PayPal USD)
• Token Address: 0xCaC524BcA292aaade2DF8A05cC58F0a65B1B3bB9
• Stablecoin integration for predictable pricing

📱 User Experience Features

Student Flow

1. Wallet Connection → Role Selection
2. Registration → Language & Budget Setup
3. Deposit Funds → PYUSD token approval
4. Find Tutor → Matchmaking system
5. Start Session → WebRTC video call
6. Real-time Billing → Per-second payments
7. Session End → Automatic settlement

Tutor Flow

1. Wallet Connection → Role Selection
2. Registration → Languages & Rates Setup
3. Go Online → Availability status
4. Accept Sessions → Student matching
5. Teach Session → WebRTC video call
6. Receive Payments → Real-time earnings

🔒 Security & Reliability

Smart Contract Security

• Access control with role-based modifiers
• Input validation for all functions
• Emergency functions for owner intervention
• Balance checks before operations

WebRTC Security

• HTTPS/WSS protocols for secure communication
• End-to-end encryption for video/audio
• Session token validation
• Heartbeat monitoring for connection health

🚀 Deployment & Infrastructure

Frontend Deployment

• Framework: Next.js with static generation
• Hosting: Vercel-ready configuration
• Environment: Production-optimized builds

Backend Deployment

• Platform: Railway.app
• URL: https://langdao-production.up.railway.app
• WebSocket: Real-time signaling server
• API: RESTful endpoints for integration

Smart Contract Deployment

• Network: Sepolia Testnet
• Verification: Etherscan-ready
• ABI: Auto-generated TypeScript interfaces

📊 Technical Metrics

Performance

• Real-time billing: Per-second accuracy
• Video latency: WebRTC optimized
• Transaction speed: Ethereum network dependent
• Heartbeat frequency: 10-second intervals

Scalability

• Multi-language support: 38 languages
• Concurrent sessions: Limited by WebRTC infrastructure
• User capacity: Wallet-based authentication
• Payment processing: PYUSD token efficiency

🛠️ Development Tools

Smart Contract Development

• Hardhat: Development framework
• TypeScript: Type safety
• Ethers.js: Contract interactions
• OpenZeppelin: Security standards

Frontend Development

• Next.js: React framework
• Tailwind CSS: Utility-first styling
• Framer Motion: Animations
• React Query: Data fetching

Testing & Quality

• ESLint: Code linting
• Prettier: Code formatting
• TypeScript: Type checking
• Hot reload: Development efficiency

🎯 Hackathon Achievements

Completed Features

✅ Full-stack Web3 application
✅ Real-time video communication
✅ Per-second billing system
✅ Multi-language support
✅ PYUSD token integration
✅ Professional UI/UX
✅ Production deployment
✅ Smart contract verification

Technical Innovation

• Per-second billing for language learning
• WebRTC + Web3 integration for real-time payments
• Multi-language matching algorithm
• Automatic session management
• Stablecoin payment system

This technical foundation positions LangDAO as a comprehensive, production-ready platform for decentralized language education with real-time payments and professional-grade video communication.