Nexus Order — On-Chain Limit Order DEX

A fully on-chain order book DEX with limit orders, built with Solidity, Foundry, and React.

Live Contract

• Network: Sepolia Testnet
• Address: 0x098622fd935216c2a14300ffc3cb5b0e08736964
• Verified: ✅ on Etherscan

Features

• ✅ Place limit buy and sell orders on-chain
• ✅ Automatic order matching engine in Solidity
• ✅ Cancel orders
• ✅ Real-time order book UI
• ✅ Wallet connect via RainbowKit
• ✅ 5 Foundry tests, all passing

Tech Stack

Layer	Technology
Smart Contracts	Solidity ^0.8.24, Foundry
Frontend	React 19, TypeScript, Vite
Web3	Wagmi, Viem, RainbowKit
Styling	Tailwind CSS v4
Testing	Forge (5/5 passing)
Network	Ethereum Sepolia Testnet

How It Works

The OrderBook smart contract stores all orders on-chain. When a new order is placed, the contract automatically runs a matching engine against existing orders. If a buy price meets a sell price, they are matched and an OrderMatched event is emitted.

Getting Started

Contracts

cd contracts
forge build
forge test -v

Frontend

cd frontend
npm install
npm run dev

Tests

• [PASS] test_CancelOrder
• [PASS] test_CannotCancelOthersOrder
• [PASS] test_OrderMatching
• [PASS] test_PlaceBuyOrder
• [PASS] test_PlaceSellOrder 5 passed; 0 failed

License

MIT