Uniswap is a decentralized exchange (DEX) protocol built primarily on Ethereum that enables permissionless token swaps through automated market maker (AMM) smart contracts rather than traditional order books. The UNI token serves as the governance asset for the Uniswap ecosystem, enabling holders to vote on protocol upgrades, fee parameters, treasury usage, and other governance proposals. The protocol is non-custodial, meaning users retain control of their wallets and interact directly with smart contracts without intermediaries.