Solidity Smart Contract Development

Develop production-ready smart contracts following security best practices and gas optimization patterns. Focus on implementing business logic as enforceable on-chain rules with proper access controls and event emissions.

Examples

Basic ERC-20 Token Implementation

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Token {
    mapping(address => uint256) public balanceOf;
    uint256 public totalSupply;
    
    function transfer(address to, uint256 amount) external {
        require(balanceOf[msg.sender] >= amount, "Insufficient balance");
        balanceOf[msg.sender] -= amount;
        balanceOf[to] += amount;
        emit Transfer(msg.sender, to, amount);
    }
}

Access Control Pattern

modifier onlyOwner() {
    require(msg.sender == owner, "Not authorized");
    _;
}

function mint(address to, uint256 amount) external onlyOwner {
    totalSupply += amount;
    balanceOf[to] += amount;
}

Business Logic Invariant

function _checkInvariant() internal view returns (bool) {
    // Example: Ensure reserves always back token supply
    return address(reserve).balance >= totalSupply;
}

function transfer(address to, uint256 amount) external {
    require(_checkInvariant(), "Invariant violated");
    // ... transfer logic
}

Guidelines

Security First

• Always use Checks-Effects-Interactions pattern
• Validate all inputs and state transitions
• Implement proper access controls
• Use OpenZeppelin contracts when available
• Consider reentrancy guards for external calls

Gas Optimization

• Pack struct variables efficiently
• Use immutable and constant where applicable
• Minimize storage operations
• Batch operations when possible
• Avoid loops with unbounded iterations

Code Quality

• Follow Solidity style guide
• Use descriptive variable and function names
• Add NatSpec comments for all public functions
• Emit events for all state changes
• Write comprehensive unit tests

Common Patterns

• Factory pattern for contract deployment
• Proxy pattern for upgradability
• Pull payment pattern for withdrawals
• Circuit breaker for emergency stops
• Time-locked administration

Testing Requirements

• Unit tests for all functions
• Edge case coverage
• Fuzzing for numeric operations
• Integration tests for contract interactions
• Gas consumption benchmarks