Smart Contracts

Smart contracts are programs deployed on a blockchain that execute automatically when specific conditions are met. They eliminate the need for intermediaries by encoding business logic directly into immutable, transparent code.

On Ethereum, smart contracts are typically written in Solidity and compiled to EVM bytecode. Once deployed, the contract's code cannot be changed (though upgradeable patterns exist). Anyone can interact with the contract by sending transactions.

Common use cases include token creation (ERC-20, ERC-721), decentralized exchanges (AMMs like Uniswap), lending protocols (Aave, Compound), governance systems (DAOs), and NFT marketplaces.

Security is paramount — smart contract bugs can lead to irreversible loss of funds. Best practices include thorough testing, formal verification, security audits, and following established patterns from OpenZeppelin. Common vulnerabilities include reentrancy attacks, integer overflow, and access control issues.