What is a decentralized exchange (DEX)?

A decentralized exchange (or DEX) is nothing more than a smart contract designed to enable trustless peer-to-peer trading via already existing wallets. With a DEX, coins only leave your wallet when they’re traded directly to another user from his or her wallet. This cuts out the middleman and makes the entire process much more streamlined.  With a DEX, traders no longer have to worry about where their coins reside. Moreover, they no longer have to feel that they're at the mercy of an exchanges’ support staff.  Perhaps more importantly, they will no longer feel compelled to register on a new exchange simply because they have no other options.