DeFi smart contract development involves building secure, self-executing code that powers decentralized finance applications like lending, staking, trading, and yield farming. These smart contracts, typically written in Solidity, automate transactions without intermediaries. Developers focus on contract logic, auditing, and testing to ensure efficiency, immutability, and security. Used on Ethereum, BNB Chain, and Polygon, DeFi smart contracts form the backbone of protocols like Uniswap and Compound. Proper development ensures trustless interactions, transparency, and rapid scalability, making it essential for launching successful DeFi products.