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Windmill EVM Contracts

Windmill EVM Contracts contains the core smart contracts of Windmill Exchange — a decentralized on-chain order matching engine with configurable dynamic pricing curves and autonomous keeper matching.

Orders (buy and sell) are submitted on-chain and continuously matched by keeper bots. Matching rewards are earned by keepers based on configurable price curves, and all settlements happen atomically on-chain.

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🔗 Repository Links

1. Web UI
2. Keeper Bots
3. Main Repository

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🚀 Features

• On-chain order matching: buy and sell orders stored on-chain in OrderStorage and PairStorage and matched atomically.
• Dynamic pricing curves: configurable PriceCurve and MathUtils libraries drive matching rewards.
• Safe token handling: TokenTransfer library with reentrancy-aware ERC20 transfers.
• Auction-based incentive model: keepers earn on each executed match.
• Foundry toolchain: build, fuzz, gas-snapshot, and Slither workflows out of the box.

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Architecture

src/
├── core/
│   └── WindmillExchange.sol   # Core exchange + matching logic
├── interfaces/
│   ├── IWindmillExchange.sol  # Public exchange interface
│   └── IERC20.sol             # Minimal ERC20 interface
├── libraries/
│   ├── MathUtils.sol          # Safe math helpers
│   ├── PriceCurve.sol         # Configurable dynamic pricing curves
│   └── TokenTransfer.sol      # Reentrancy-aware token transfers
└── storage/
    ├── OrderStorage.sol       # Order book storage
    └── PairStorage.sol        # Trading pair storage

script/
└── DeployWindmill.s.sol       # Deployment script (Foundry)

test/
└── WindmillExchange.t.sol     # Core test suite

Flow

flowchart LR
    U[User / Trader] -->|placeOrder| X(WindmillExchange)
    K[Keeper Bot] -->|match/matchExecution| X
    X -->|store| OS[(OrderStorage)]
    X -->|price curve| PC[[PriceCurve]]
    X -->|transfer| TT[[TokenTransfer]]
    X -->|settle + pay keeper| U
    K -.->|scan events| X

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🛠️ Tech Stack

Layer	Technology
Language	Solidity ^0.8.23
Framework	Foundry (forge, cast, anvil)
Libraries	OpenZeppelin + forge-std (via lib/)
Static analysis	Slither (CI)

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📁 Repository Structure

.
├── .github/workflows/     # CI, security, gas, fuzz, release pipelines
├── lib/                   # Foundry dependencies (git submodules)
├── public/                # Logos and static assets
├── script/                # Forge deployment scripts
├── src/                   # Solidity source contracts
├── test/                  # Forge test suite
├── foundry.toml           # Foundry config (RPCs, verifiers)
├── foundry.lock           # Locked dependency versions
├── Deployments.md         # Deployment records
└── README.md

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🚀 Getting Started

Prerequisites

Tool	Version	Install
git	any	git-scm.com
foundryup	latest	See getfoundry.sh
forge / cast / anvil	latest	run foundryup after install

Verify installation:

forge --version
anvil --version
cast --version

Installation

# 1. Clone with submodules
git clone --recurse-submodules https://github.com/StabilityNexus/Windmill-EVM-Contracts
cd Windmill-EVM-Contracts

# 2. If you forgot --recurse-submodules
git submodule update --init --recursive

# 3. Install/update Foundry dependencies
forge install

Build

forge build

Test

# Run all tests
forge test

# Verbose output (logs and traces)
forge test -vvv

# Run a specific test
forge test --match-test testMatchOrders -vvv

Coverage

forge coverage
forge coverage --report lcov
genhtml lcov.info --output-directory coverage/

Gas Snapshot

forge snapshot          # generate snapshot
forge snapshot --diff   # compare against last snapshot

Format & Lint

forge fmt              # format Solidity files
forge fmt --check      # check without writing (used in CI)

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🔧 Deployment

Make sure your .env is configured before deploying. See .env.example and Deployments.md.

# Fork-test / local deployment with Anvil
anvil   # in one terminal

# Deploy (set RPC url for your target network)
forge script script/DeployWindmill.s.sol \
  --rpc-url <RPC_URL> \
  --broadcast \
  --verify \
  -vvvv

RPC aliases (ethereum, sepolia, base, polygon, etc.) are pre-configured in foundry.toml.

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Supported Networks

Network	Chain ID
Ethereum (Mainnet)	1
Ethereum Classic (Mainnet)	61
Polygon PoS (Mainnet)	137
BNB Smart Chain (Mainnet)	56
Base (Mainnet)	8453
Avalanche C-Chain (Mainnet)	43114
Sepolia (Testnet)	11155111
Mordor (ETC Testnet)	63

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CI/CD Workflows

Workflow	Trigger	What it does
ci.yml	Push / PR	Format check → Build → Unit tests → Coverage report
security-slither.yml	Push / PR	Slither static analysis for vulnerabilities
gas-snapshot.yml	Push / PR	Gas baseline and regression checks
nightly-fuzz.yml	Nightly (cron)	Deep fuzz & invariant testing
release.yml	Tag push	Builds and publishes release artifacts

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🔒 Security

• Static analysis is run on every PR via Slither (.github/workflows/security-slither.yml).
• CodeRabbit AI review is enabled via .coderabbit.yaml.
• Deep fuzz runs nightly to catch edge cases.

Found a vulnerability? Please do not open a public issue. Contact the Stability Nexus team privately via Discord or Telegram.

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🙌 Contributing

⭐ Don't forget to star this repository if you find it useful! ⭐

Thank you for considering contributing to this project! Please read our Contribution Guidelines first — they cover the mandatory Discord workflow and our AI-use disclosure policy.

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📍 License

See COPYRIGHT.md and DCO.md for intellectual property and sign-off details.

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💪 Thanks To All Contributors

© Stability Nexus