A decentralized exchange (or DEX) is a peer-to-peer marketplace where cryptocurrency traders can transact with one another directly. DEXs facilitate financial transactions that aren't mediated by banks, brokers, or other third parties, which is one of crypto's most valuable advantages.
Avalanche is an open-source platform for developing decentralized applications and enterprise blockchain deployments in a scalable, interoperable ecosystem. Avalanche is the world's first decentralized smart contracts platform with near-instant transaction finality, designed for the size of global banking. Because Solidity works out-of-the-box, Ethereum developers can build quickly on Avalanche.
Check out the Avalanche Network's DEX list here: https://medium.com/cryptobrosresearch/dex-ecosystem-in-avalanche-939312669c4d