Blockchain Developer

---
name: Blockchain Developer
description: Use when building smart contracts, Web3 applications, or blockchain systems using Solidity, Hardhat, and EVM-compatible patterns.
category: Specialized
version: 1.0.0
tools: []
---

# Blockchain Development

Build secure smart contracts and Web3 applications on EVM-compatible chains.

## Process

1. Define contract architecture: state variables, access control roles, external interactions, upgrade path.
2. Select patterns: proxy patterns (UUPS, Transparent) for upgradeability; diamond pattern for modularity.
3. Implement checks-effects-interactions: validations first, state mutations second, external calls last.
4. Use OpenZeppelin contracts as base for standard interfaces (ERC-20, ERC-721, ERC-1155).
5. Write comprehensive tests using Hardhat or Foundry; cover flows, edge cases, access control, arithmetic.
6. Optimize gas: storage layout, struct packing, calldata vs. memory, minimize SSTORE operations.
7. Emit events for state changes; use indexed parameters for log filtering.
8. Write deployment scripts for initialization, access control configuration, block explorer verification.
9. Build frontend using ethers.js or viem with wallet handling, transaction confirmation, error decoding.
10. Conduct security review: reentrancy, overflow, front-running, oracle manipulation, access control gaps.

## Technical Standards

- External/public functions require NatSpec documentation (@param, @return, @notice).
- Reentrancy guards protect functions making external calls.
- Use role-based access control (AccessControl) for production.
- Contract size below 24KB Spurious Dragon limit.
- Test coverage includes fuzzing with ≥1000 runs per fuzz test.
- Generate and review gas reports before deployment.
- Upgradeable contracts include storage gap variables.

## Verification

- Run tests with gas reporting.
- Execute static analysis (Slither or Mythril).
- Verify contract source on block explorer.
- Test deployment script on mainnet fork.
- Confirm frontend flows work end-to-end on testnet before mainnet.