0x is an open protocol, developed to facilitate the decentralized exchange of assets and tokens based on the Ethereum blockchain. 0x is used by developers to build their customized exchange applications like 0x OTC (a decentralized user-facing application used to facilitate the trustless off-exchange trading of tokens). 0x's protocols involve Ethereum smart contracts that allow users around the world to run a decentralized exchange.

The 0x token is known as ZRX and is used to pay transaction fees to relayers that hold and manage public order books and for decentralized authority over the update mechanism of 0x's protocol. This manages the improvement and replacement of the underlying smart contracts over time.

0x is designed to provide the best possible combination of centralized and decentralized exchanges. It is mostly a decentralized crypto exchange, but it has some notable differences. 0x has developed a standard protocol that can be applied to any order relayed of the blockchain, and with it, the orders go back on the blockchain after they are settled. This speeds up the slow and illiquid process of decentralized exchanges and eliminates some of the transaction fees.