0x (ZRX) is an open protocol that makes decentralized exchange of Ethereum-based tokens and assets straightforward. Developers can use 0x to build their own exchange applications across a wide range of user-facing use cases - in other words, 0x is a decentralized layer that simplifies trading tokens built on Ethereum.

The ZRX token is used by makers and takers to pay trading fees to relayers - the parties that host and maintain public order books. ZRX also powers decentralized governance of the 0x protocol's upgrade mechanism, which allows its underlying smart contracts to be replaced and improved over time.