0x (ZRX) is an open protocol for decentralized exchange on the Ethereum blockchain. It is intended to serve as a basic building block that may be combined with other protocols to drive increasingly sophisticated dApps. 0x uses a publicly accessible system of smart contracts that can act as shared infrastructure for a variety of dApps.
Ethfinex works closely with the 0x team in working to bring about our shared vision of an entirely decentralised exchange ecosystem.
Learn more here.