| name | software-crypto-web3 |
| description | Production-grade blockchain and Web3 development with Solidity (Ethereum/EVM), Rust (Solana), CosmWasm (Cosmos), including smart contract architecture, security patterns, gas optimization, testing strategies, DeFi protocols, and deployment workflows. |
Blockchain & Web3 Development Skill — Quick Reference
This skill equips blockchain developers with execution-ready patterns for building secure, gas-optimized smart contracts and decentralized applications. Claude should apply these patterns when users ask for smart contract development, DeFi protocols, NFT implementations, security audits, or Web3 architecture.
Modern Best Practices: Security-first development, formal verification, comprehensive testing (unit, integration, fork, invariant), gas optimization, upgradeable contracts, multi-chain deployment, and battle-tested DeFi patterns.
Quick Reference
| Task | Tool/Framework | Command | When to Use |
|---|
| Solidity Development | Hardhat/Foundry | npx hardhat init or forge init | Ethereum/EVM smart contracts |
| Solana Programs | Anchor | anchor init | Solana blockchain development |
| Cosmos Contracts | CosmWasm | cargo generate --git cosmwasm-template | Cosmos ecosystem contracts |
| TON Contracts | Tact/FunC + Blueprint | npm create ton@latest | TON blockchain development |
| Testing (Solidity) | Foundry/Hardhat | forge test or npx hardhat test | Unit, fork, invariant tests |
| Security Audit | Slither/Mythril/Echidna | slither . | Static analysis, fuzzing |
| Gas Optimization | Foundry Gas Snapshots | forge snapshot | Benchmark and optimize gas |
| Deployment | Hardhat Deploy/Forge Script | npx hardhat deploy | Mainnet/testnet deployment |
| Verification | Etherscan API | npx hardhat verify | Source code verification |
| Upgradeable Contracts | OpenZeppelin Upgrades | @openzeppelin/hardhat-upgrades | Proxy-based upgrades |
When to Use This Skill
Claude should invoke this skill when a user requests:
- Smart contract development (Solidity, Rust, CosmWasm)
- DeFi protocol implementation (AMM, lending, staking, yield farming)
- NFT and token standards (ERC20, ERC721, ERC1155, SPL tokens)
- DAO governance systems
- Cross-chain bridges and interoperability
- Gas optimization and storage patterns
- Smart contract security audits
- Testing strategies (Foundry, Hardhat, Anchor)
- Oracle integration (Chainlink, Pyth)
- Upgradeable contract patterns (proxies, diamonds)
- Web3 frontend integration (ethers.js, web3.js, @solana/web3.js)
- Blockchain indexing (The Graph, subgraphs)
- MEV protection and flashbots
- Layer 2 scaling solutions (Optimism, Arbitrum, zkSync)
- Backend crypto integration (.NET/C#, multi-provider architecture, CQRS)
- Webhook handling and signature validation (Fireblocks, custodial providers)
- Event-driven architecture with Kafka for crypto payments
- Transaction lifecycle management and monitoring
- Wallet management (custodial vs non-custodial)
Decision Tree: Blockchain Platform Selection
Project needs: [Use Case]
├─ EVM-compatible smart contracts?
│ ├─ Complex testing needs → Foundry (Solidity tests, fuzzing, gas snapshots)
│ ├─ TypeScript ecosystem → Hardhat (plugins, TypeScript, Ethers.js)
│ └─ Enterprise features → NestJS + Hardhat
│
├─ High throughput/low fees?
│ ├─ Rust-based → Solana (Anchor framework, 50k+ TPS)
│ ├─ EVM L2 → Arbitrum/Optimism (Ethereum security, lower gas)
│ └─ Telegram integration → TON (Tact/FunC contracts)
│
├─ Interoperability across chains?
│ ├─ Cosmos ecosystem → CosmWasm (IBC protocol)
│ ├─ Multi-chain DeFi → LayerZero or Wormhole
│ └─ Bridge development → Custom bridge contracts
│
├─ Token standard implementation?
│ ├─ Fungible tokens → ERC20 (OpenZeppelin), SPL Token (Solana)
│ ├─ NFTs → ERC721/ERC1155 (OpenZeppelin), Metaplex (Solana)
│ └─ Semi-fungible → ERC1155 (gaming, fractionalized NFTs)
│
├─ DeFi protocol development?
│ ├─ AMM/DEX → Uniswap V3 fork or custom (x*y=k, concentrated liquidity)
│ ├─ Lending → Compound/Aave fork (collateralized borrowing)
│ └─ Staking/Yield → Custom reward distribution contracts
│
├─ Upgradeable contracts required?
│ ├─ Transparent Proxy → OpenZeppelin (admin/user separation)
│ ├─ UUPS → Gas-efficient (upgrade logic in implementation)
│ └─ Diamond Standard → Modular functionality (EIP-2535)
│
└─ Backend integration?
├─ .NET/C# → Multi-provider architecture (see Backend Integration Patterns)
├─ Node.js → Ethers.js/Web3.js + Prisma
└─ Python → Web3.py + FastAPI
Chain-Specific Considerations:
- Ethereum/EVM: Security-first, higher gas costs, largest ecosystem
- Solana: Performance-first, Rust required, lower fees
- Cosmos: Interoperability-first, IBC native, growing ecosystem
- TON: Telegram-first, async contracts, unique architecture
See resources/ for chain-specific best practices.
Navigation
Resources
Templates
Related Skills
- ../software-security-appsec/SKILL.md — Security hardening, threat modeling, OWASP vulnerabilities
- ../software-architecture-design/SKILL.md — System decomposition, modularity, dependency design
- ../ops-devops-platform/SKILL.md — Infrastructure, CI/CD, observability for blockchain nodes
- ../software-backend/SKILL.md — API integration with smart contracts, RPC nodes, indexers
- ../quality-resilience-patterns/SKILL.md — Resilience, circuit breakers, retry logic for chains
- ../software-code-review/SKILL.md — Code review patterns and quality gates
- ../foundation-api-design/SKILL.md — RESTful design for Web3 APIs and dApp backends
Operational Playbooks
