Uniswap Multi-Chain Token Swap DApp

A TypeScript-based decentralized application for swapping tokens across multiple EVM chains using the Uniswap V3 SDK.

Features

🔗 Multi-Chain Support: Ethereum, Base, Arbitrum, BNB Smart Chain
💱 Token Swaps: Support for all major tokens (ETH, WETH, USDC, USDT, DAI, etc.)
⛽ Gas Optimization: Efficient gas usage with Uniswap V3
🔐 Secure: Non-custodial swaps directly from your wallet
📊 Real-time Quotes: Live pricing and slippage calculation
🚀 Easy Integration: Simple API for developers

Supported Chains

Chain	Chain ID	Status	Native Token
Ethereum	1	✅	ETH
Base	8453	✅	ETH
Arbitrum One	42161	✅	ETH
BNB Smart Chain	56	✅	BNB

Quick Start

Installation

npm install

Environment Setup

Create a .env file:

# Optional: Add your private key for swap execution
PRIVATE_KEY=your_private_key_here

# Optional: Custom RPC URLs
ETHEREUM_RPC_URL=your_ethereum_rpc
BASE_RPC_URL=your_base_rpc
ARBITRUM_RPC_URL=your_arbitrum_rpc
BNB_RPC_URL=your_bnb_rpc

Running Demos

# General multi-chain demo
npm run demo

# Base network specific demo (ETH ↔ USDT)
npm run demo-base

# Build only
npm run build

Base Network Demo (ETH ↔ USDT)

The Base demo specifically demonstrates native ETH to USDT swaps:

Features Demonstrated

✅ ETH → USDT Swap Quotes
✅ USDT → ETH Swap Quotes
✅ Token Balance Checking
✅ Allowance Management
✅ Transaction Preparation
✅ Real-time Exchange Rates

Example Output

🟡 Base Network Token Swap Demo
==================================================
📍 Network: Base (Chain ID: 8453)
🔗 Native Token: ETH
💱 Demo Swaps: ETH ↔ USDT
==================================================

📊 Example 1: ETH → USDT Swap Quote
----------------------------------------
💰 Input: 0.1 ETH (Native)
💰 Expected Output: 254.32 USDT
⛽ Estimated Gas: 150000
📈 Price Impact: 0.1%
🛣️  Route: ETH → USDT
💱 Exchange Rate: 1 ETH = 2543.20 USDT
ℹ️  Note: ETH will be automatically wrapped to WETH during swap

How It Works

1. ETH Input: You provide native ETH
2. Auto-Wrapping: ETH is automatically wrapped to WETH
3. Uniswap Swap: WETH is swapped to USDT via Uniswap V3
4. Direct Delivery: USDT is sent to your address

For the reverse (USDT → ETH):

1. USDT Input: You provide USDT (requires approval)
2. Uniswap Swap: USDT is swapped to WETH
3. Auto-Unwrapping: WETH is unwrapped to native ETH
4. Direct Delivery: ETH is sent to your address

Usage Examples

Getting a Quote

import { SwapService } from './src/swapper';
import { COMMON_TOKENS } from './src/config';

// Initialize for Base network
const swapService = new SwapService(8453);
const tokens = COMMON_TOKENS[8453];

// Get ETH to USDT quote
const quote = await swapService.getEthToTokenQuote(
  tokens.USDT,
  '0.1' // 0.1 ETH
);

console.log(`1 ETH = ${quote.amountOut / 0.1} USDT`);

Executing a Swap

// Initialize with private key for execution
const swapService = new SwapService(8453, 'your_private_key');

// Execute ETH to USDT swap
const result = await swapService.executeEthToTokenSwap({
  tokenOut: tokens.USDT,
  amountIn: '0.1',
  slippageTolerance: 0.5, // 0.5%
  deadline: 1800, // 30 minutes
  recipient: 'your_wallet_address',
});

console.log(`Swap completed: ${result.hash}`);

Checking Balances

// Check ETH balance
const provider = new ethers.JsonRpcProvider('https://mainnet.base.org');
const ethBalance = await provider.getBalance('your_address');

// Check USDT balance
const usdtBalance = await swapService.getTokenBalance(
  tokens.USDT.address,
  'your_address'
);

Token Addresses (Base Network)

Token	Address	Decimals
WETH	0x4200000000000000000000000000000000000006	18
USDC	0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913	6
USDT	0xfde4C96c8593536E31F229EA8f37b2ADa2699bb2	6
DAI	0x50c5725949A6F0c72E6C4a641F24049A917DB0Cb	18

Uniswap Contracts (Base)

Contract	Address
Swap Router	0x2626664c2603336E57B271c5C0b26F421741e481
Quoter	0x3d4e44Eb1374240CE5F1B871ab261CD16335B76a

Safety Guidelines

⚠️ Important Notes:

1. Test First: Always test with small amounts
2. Slippage: Set appropriate slippage tolerance (0.5-3%)
3. Gas Fees: Ensure sufficient ETH for gas
4. Approvals: USDT swaps require token approval first
5. Private Keys: Never share your private keys
6. Testnet: Use testnets for development

Architecture

src/
├── types.ts          # TypeScript interfaces
├── config.ts         # Chain and token configurations
├── swapper.ts        # Core swap service
└── demo.ts           # Multi-chain demo

demo-base.ts          # Base-specific demo

Dependencies

• @uniswap/sdk-core: Core Uniswap SDK
• @uniswap/v3-sdk: Uniswap V3 specific functionality
• @uniswap/router-sdk: Router SDK for swaps
• ethers: Ethereum library for blockchain interaction

License

MIT

Disclaimer

This software is provided for educational purposes. Always verify transactions and use at your own risk. The authors are not responsible for any financial losses.