Decentralized exchange (DEX)

A decentralized exchange (DEX) lets users trade cryptocurrencies directly from their own wallets through self-executing smart contracts, rather than depositing funds with a central company that matches orders and holds custody, as a traditional or centralized exchange does. Trades settle on-chain, and the exchange itself never takes custody of user assets.

Most DEXs use an automated market maker (AMM) model, where trades execute against a pooled reserve of two assets governed by a pricing formula, commonly x × y = k, rather than a traditional order book matching buyers and sellers directly. Liquidity providers deposit assets into these pools and earn a share of trading fees in return, taking on the risk of impermanent loss if the pool's asset prices diverge. Every trade on a DEX also requires paying gas fees to the underlying blockchain to execute the smart contract, unlike a centralized exchange's flat trading fee.

DEXs matter because they remove counterparty and custody risk tied to a single company, at the cost of user responsibility for wallet security and exposure to smart contract bugs. Activity across DEXs, tracked through on-chain analytics and metrics like total value locked, is a widely used gauge of decentralized finance adoption. A common pitfall is assuming "decentralized" means risk-free: smart contract exploits, price manipulation within thin pools, and wallet clustering deanonymization remain real risks.