Yearn Finance is a decentralized protocol that aggregates user capital into vaults, each of which earns yield by deploying capital across multiple DeFi strategies. A strategy is a smart contract that automates yield farming: it borrows funds from the vault, executes trades (e.g., swapping into a liquidity pool, lending on Aave), harvests yield (including governance tokens), and returns capital plus earnings to the vault. Yearn operates on multiple blockchains (Ethereum, Polygon, Arbitrum, Optimism) and manages billions in assets under management (AUM). Strategy developers write Solidity contracts that integrate with external protocols, implement risk controls, optimize gas costs, and pass security audits before deployment. The role blends smart contract development, DeFi protocol knowledge, quantitative analysis, and operational security.