Solidity

What is Solidity?

Solidity is the primary programming language used to write smart contracts on Ethereum and other EVM-compatible blockchains (like BNB Chain, Polygon, Avalanche). Created by Ethereum co-founder Gavin Wood, it’s specifically designed for blockchain development and runs on the Ethereum Virtual Machine (EVM).

Why Solidity Matters

Powers DeFi

• Uniswap, Aave, Compound built with Solidity
• Billions of dollars secured by Solidity contracts
• Foundation of decentralized applications

Industry Standard

• Most widely-used smart contract language
• Large developer community
• Extensive tools and documentation

Solidity Basics

What It Looks Like

// Simple token contract
contract MyToken {
    mapping(address => uint256) public balances;

    function transfer(address to, uint256 amount) public {
        require(balances[msg.sender] >= amount, "Insufficient balance");
        balances[msg.sender] -= amount;
        balances[to] += amount;
    }
}

Key Features

• Statically typed: Variable types declared upfront
• Contract-oriented: Organized around contracts
• Inheritance: Contracts can inherit from others
• Libraries: Reusable code modules

What Solidity Creates

Application	Example
Tokens	ERC-20 (USDT, LINK)
NFTs	ERC-721 (CryptoPunks, BAYC)
DEXs	Uniswap, SushiSwap
Lending	Aave, Compound
DAOs	Governance contracts

Solidity vs Other Languages

Language	Blockchain	Use Case
Solidity	Ethereum/EVM	Most dApps
Rust	Solana	High-performance
Vyper	Ethereum	Security-focused
Move	Aptos/Sui	Asset-oriented

Security Considerations

Solidity contracts are immutable and handle real money, making security critical:

Common Vulnerabilities

• Reentrancy: Recursive calling exploits
• Integer overflow: Math errors
• Access control: Missing permission checks

Best Practices

• Professional audits before deployment
• Use established libraries (OpenZeppelin)
• Extensive testing
• Bug bounty programs

Why This Matters for Traders

Understanding Solidity helps you:

• Evaluate DeFi protocol security
• Recognize red flags in new projects
• Understand gas fee mechanics
• Make informed investment decisions

Most traders interact with Solidity contracts through user interfaces on exchanges like Coinbase and DeFi platforms, without needing to code themselves.

Learning Solidity

Resources for those interested:

• CryptoZombies (interactive tutorials)
• Ethereum documentation
• OpenZeppelin contracts
• Solidity by Example