EVM Blackjack Casino – Provably Fair Blackjack with Web3 Wallet Payments (No Smart Contracts)

A production-ready, full-stack web application for a provably fair Blackjack casino game. Features centralized game logic with cryptographic provable fairness and Web3 wallet integration (MetaMask/WalletConnect) for EVM-based deposits, bets, and payouts. No smart contracts required – all game logic runs off-chain with transparent, verifiable randomness.

🎲 Features

Provably Fair: Cryptographic seed-based system (server seed hash pre-commit + client seed + nonce) using HMAC-SHA256 for deterministic card shuffling
Web3 Wallet Integration: Seamless MetaMask and WalletConnect support via wagmi/viem
Multi-Chain Support: Ethereum, Base, Arbitrum, Polygon (configurable)
Classic Blackjack Rules: Hit, Stand, Double, Split, Insurance with proper payout calculations (3:2 blackjack, 1:1 win, 2:1 insurance)
Real-Time Balance Tracking: Off-chain balance management with on-chain deposit confirmations
Transaction Transparency: All deposits and payouts tracked with transaction hashes
Beautiful UI: Dark casino theme with Framer Motion animations, card flips, confetti on wins
Verification Tool: Built-in provably fair verification component to recompute and verify any hand
Responsive Design: Works on desktop and mobile devices

🛠 Tech Stack

Backend

Node.js + Express + TypeScript
SQLite database (easily swappable to PostgreSQL/MySQL)
ethers.js for EVM transaction verification
JWT for wallet-based authentication
Rate limiting and security middleware

Frontend

React 19 + Vite + TypeScript
Tailwind CSS v4 for styling
Framer Motion for animations
wagmi + viem for Web3 wallet integration
React Query for data fetching
React Hot Toast for notifications

Provably Fair

HMAC-SHA256 for deterministic randomness
Fisher-Yates shuffle with cryptographic seed
Server seed pre-commit (hash shown before hand)
Client seed (user-provided or auto-generated)
Nonce for uniqueness

📋 Prerequisites

Node.js 18+ and npm/yarn
MetaMask or compatible Web3 wallet
EVM-compatible network (Ethereum, Base, Arbitrum, or Polygon)
Basic knowledge of Web3 wallets and EVM transactions

🚀 Installation & Setup

1. Clone the Repository

git clone <repository-url>
cd EVM-Blackjack-Casino-1

2. Install Dependencies

# Install all workspace dependencies
npm install

This will install dependencies for:

Root workspace
Backend (backend/)
Frontend (frontend/)
Shared (shared/)

3. Configure Environment Variables

Create .env files in the root and backend directories:

Root .env (optional, for frontend):

VITE_API_URL=http://localhost:3001/api
VITE_HOUSE_WALLET=0xYourHouseWalletAddress
VITE_WALLETCONNECT_PROJECT_ID=your-walletconnect-project-id

Backend .env:

PORT=3001
NODE_ENV=development
JWT_SECRET=your-super-secret-jwt-key-change-in-production

# House wallet that receives deposits
HOUSE_WALLET_ADDRESS=0xYourHouseWalletAddress

# Supported chains (comma-separated)
SUPPORTED_CHAINS=1,8453,42161,137
DEFAULT_CHAIN_ID=1

# RPC URLs for transaction polling
ETHEREUM_RPC_URL=https://eth-mainnet.g.alchemy.com/v2/YOUR_API_KEY
BASE_RPC_URL=https://base-mainnet.g.alchemy.com/v2/YOUR_API_KEY
ARBITRUM_RPC_URL=https://arb-mainnet.g.alchemy.com/v2/YOUR_API_KEY
POLYGON_RPC_URL=https://polygon-mainnet.g.alchemy.com/v2/YOUR_API_KEY

# Transaction polling
TX_POLL_INTERVAL_MS=5000
TX_CONFIRMATION_BLOCKS=3

# Rate limiting
RATE_LIMIT_WINDOW_MS=60000
RATE_LIMIT_MAX_REQUESTS=100

# Database
DB_PATH=./data/casino.db

4. Build Shared Package

cd shared
npm run build
cd ..

5. Start Development Servers

Option A: Run both simultaneously

npm run dev

Option B: Run separately

# Terminal 1: Backend
npm run dev:backend

# Terminal 2: Frontend
npm run dev:frontend

The backend will run on http://localhost:3001 and the frontend on http://localhost:5173.

🎮 How to Play

1. Connect Wallet

Click "Connect Wallet" and select MetaMask or WalletConnect
Sign the authentication message to verify wallet ownership
Your wallet address is now linked to your account

2. Deposit Funds

Click "Deposit" button
Enter amount in ETH
Send transaction to the house wallet address (shown with QR code)
Wait for confirmations (typically 3 blocks)
Balance updates automatically

3. Play Blackjack

Set your bet amount (minimum 0.01 ETH)
Optionally set a client seed (or use random)
Click "Deal Cards"
Server seed hash is shown (pre-commit for provable fairness)
Make decisions: Hit, Stand, Double, Split, or Insurance
Dealer plays automatically
Win/loss determined and balance updated

4. Verify Fairness

Click "Verify" button
Enter server seed hash, revealed server seed, client seed, and nonce
Click "Verify" to recompute the shuffle
Compare results with actual cards dealt

5. Withdraw Winnings

Click "Withdraw" button
Enter amount and destination address
Submit withdrawal request
Admin processes manually (in production, automate with scripts)

📧 Support

Telegram: https://t.me/CasinoCutup
Twitter: https://x.com/CasinoCutup

casinocutup/EVM-Blackjack-Casino