Uniswap is a decentralized exchange protocol launched in 2018 on the Ethereum blockchain. It uses an automated market maker (AMM) model, allowing users to trade ERC-20 tokens directly from their wallets without relying on centralized intermediaries. Liquidity providers supply tokens to pools and earn fees from trades, making Uniswap a key player in decentralized finance (DeFi) and one of the most widely used DEX platforms in the crypto ecosystem.