💱 SimpleSwap DEX

📜 Overview

SimpleSwap is a DEX implemented in Solidity that enables:

• ✅ Adding liquidity between two ERC20 tokens
• 🔁 Swapping tokens with exact input amounts
• 💧 Removing proportional liquidity
• 📊 Querying current prices and swap estimates

All interactions are protected with input validation and deadline constraints to ensure safe and fair operations.

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🌐 Frontend on Vercel (Next.js)

The web application is deployed on Vercel and interacts with the contracts on Sepolia.

🔗 Live Demo: https://simple-swap-amm-nextjs.vercel.app/

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🛠️ Smart Contracts

Core Contracts

• 🔁 SimpleSwap: Manages liquidity pools and token swaps
• 💧 ERC20 Tokens: Dynamically generated via TokenFactory
• 🧱 LP Tokens: The SimpleSwap contract also acts as a liquidity token (inherits from ERC20)

Deployed Addresses (Sepolia)

• BOOKE (Bokita Coin): 0x3b6BEcE5Ec2Ac59c073B085D32D0962E2911bae8
• MIAMI (General Coin): 0xf622c8a6634BC87C9cE4eC40C4Cf6Fccf257c9A1
• SimpleSwap: 0xb4E6d982Bb76c02a510B2144e810470bd08616Bb

Key Features

Liquidity

• addLiquidity(...)
• removeLiquidity(...)

Swaps

• swapExactTokensForTokens(...)

Queries

• getPrice(...)
• getAmountOut(...)

Math Helpers

• min(uint a, uint b)
• sqrt(uint y)

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✅ Tests and Coverage

The smart contracts reach ~65% coverage across statements, branches, functions, and lines. Tests use Hardhat and Chai. Run them with:

cd packages/hardhat
npx hardhat coverage

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🚀 Deployment and Verification

Contracts are automatically deployed to the Sepolia testnet and verified on Etherscan (if a valid API key is provided).

To deploy:

cd packages/hardhat
yarn deploy

📈 How It Works

1. Add Liquidity

The user calls addLiquidity() with the selected ERC20 tokens. The contract calculates the optimal ratio and mints LP tokens to the provider.

2. Swap Tokens

The user calls swapExactTokensForTokens() to exchange a fixed amount of one token for another, based on current reserves.

3. Remove Liquidity

The user burns LP tokens via removeLiquidity() and receives a proportional share of both tokens.

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🧠 Security

• ✅ Deadline validations
• ✅ Reserve and amount checks
• ✅ Explicit reverts for failed transfers

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📂 Interface: ISimpleSwap

The ISimpleSwap interface standardizes all core functions, ensuring compatibility with external tools and explorer verification.

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🧪 Example Usage

// Add liquidity
simpleSwap.addLiquidity(
  tokenA,
  tokenB,
  1000,
  1000,
  900,
  900,
  msg.sender,
  block.timestamp + 120
);

// Swap tokens
simpleSwap.swapExactTokensForTokens(
  1000,
  900,
  [tokenA, tokenB],
  msg.sender,
  block.timestamp + 120
);

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🧱 Project Structure

simple-swap/
├── packages/
│   ├── hardhat/         # Contracts and deployment scripts
│   └── nextjs/          # Next.js frontend
├── deployments/         # Contracts generated at deploy time (copied to frontend)

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🧾 License

MIT © 2025