Senior Solidity Engineer with 5+ years crafting secure Ethereum/DeFi contracts. TypeScript pro for bulletproof dApps. DM for collabs! 🚀

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• Python for automation scripts.

• Decentralized Exchange (DEX) with Staking:

This repository showcases a production-grade Decentralized Exchange (DEX) with an Automated Market Maker (AMM) mechanism and staking for liquidity providers. As a Senior Solidity Developer with 5+ years of experience, this project demonstrates expertise in secure, gas-optimized smart contracts, including ERC-20 standards, liquidity pools, constant-product AMM (x * y = k, where k is the invariant ensuring price stability through reserve balances), multi-hop swaps, and time-weighted reward staking. The code adheres to best practices like the Checks-Effects-Interactions (CEI) pattern (validate inputs first, update state second, interact externally last to prevent reentrancy attacks) and formal verification readiness.

This DEX enables token creation, pair factories, liquidity provision/removal with LP tokens, token swaps with slippage controls, and staking of LP tokens for rewards. It's fully functional out-of-the-box, deployable to any EVM-compatible chain, and optimized for low gas costs (e.g., using immutable variables and native overflow checks in Solidity 0.8.30).

• ERC-20 Tokens: Custom tokens with mint/burn, role-based access, permits for gasless approvals, and pausability.
• Factory & Pairs: Dynamic pair creation with sorted tokens; AMM pools with invariant checks and 0.3% swap fees (deducted from input, added to reserves for LP incentives).
• Router: User-friendly for adding/removing liquidity, exact-input/output swaps, multi-hop paths, and deadline enforcement.
• Staking: Yield farming with accumulator pattern (cumulative rewards per staked unit for O(1) efficiency, avoiding loops), APY calculations, and emergency functions.
• Security: ReentrancyGuard, Pausable, flash loan resistance (post-swap invariant checks), and role separation (e.g., MINTER_ROLE).
• Testing: 100% coverage with Hardhat/Chai, including edge cases like zero liquidity and reentrancy simulations.

1. Token.sol: Extensible ERC-20 with permits and roles.
2. Factory.sol: Pair factory with event indexing and feeTo control.
3. Pair.sol: Core AMM with optimized math (Babylonian sqrt for roots) and fee-on-transfer support.
4. Router.sol: Routing for swaps and liquidity with multi-path efficiency.
5. Staking.sol: Proportional rewards with time multipliers and pause/emergency withdraw.

• Node.js v22+: Install from nodejs.org (Windows 11 compatible).
• Hardhat ^2.22.10: Global install with npm i -g hardhat.
• MetaMask: For testnet interactions.
• Ethereum Testnet: Sepolia recommended; use Alchemy for RPC (free key at alchemy.com).
• Windows 11 Notes: Use VS Code terminal; no issues with TS/Python 3.11 env for scripts.

1. Clone the repo: git clone https://github.com/1337niy/DEX.git then cd DEX.
2. Install dependencies: npm install.
3. Initialize Hardhat (if not done): npx hardhat init (select TypeScript).
4. Configure .env`: Add PRIVATE_KEY, ALCHEMY_API_KEY, ETHERSCAN_API_KEY (never commit!).
5. Update hardhat.config.ts if needed: Solidity 0.8.30 with optimizer enabled.

Run full suite: npm run test (or npx hardhat test).

• Covers deployment, liquidity ops, swaps, staking accrual, and security simulations.
• CI/CD: Automated on every push via GitHub Actions (see badge above).

1. Compile: npx hardhat compile.
2. Deploy: npm run deploy (updates scripts/deploy.ts to handle all contracts sequentially on Sepolia).
3. Verify: npm run verify for Etherscan (public code transparency).

1. Add Liquidity: Approve router, call addLiquidity with tokens/amounts/min/deadline.
2. Swap Tokens: Approve input, call swapExactTokensForTokens with amountIn/minOut/path/deadline.
3. Stake LP: Approve staking, call stake(amount).
4. Claim Rewards: Call claimReward(); withdraw with withdraw(amount).

Interact via ethers.js (TS compatible) or Remix.

• Audits: Code audit-ready with OZ libraries; CEI pattern, no external calls in critical paths.
• Risks Mitigated: Reentrancy (guards), overflow (native checks), flash loans (invariant validation), MEV (deadlines).
• Best Practices: Immutable state, events for off-chain monitoring, role-based access.

• Token → Base assets.
• Factory → Creates pairs.
• Pair → AMM logic.
• Router → User gateway.
• Staking → Rewards engine.

• Integrate React frontend with ethers.js (TS).
• Add 0.3% fees customization.
• Support ERC-721 for NFT staking.
• Formal verification with Certora.

MIT License.

Contribute or connect-let's build DeFi innovations!

Seasoned Solidity dev with 5+ yrs shipping audited DeFi protocols that handle $100M+ TVL-cut gas by 50% in prod swaps, thwarted exploits via CEI mastery. Bring battle-tested Ethereum smarts to your crypto crew: optimize, secure, and scale your dApp game. Remote-ready-let's crush web3!

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