ZRX is an ERC-standard token created to back the 0x protocol. The protocol's main goal is to assist developers in decentralized exchange creation and connecting it to their Web3 applications. 0x supports tools for selling, buying, and trading both fungible and non-fungible Ethereum tokens on various apps supporting the protocol. The ZRX token fulfills governance utility for the 0x platform. It is also used to charge transaction fees and to pay rewards for participating in liquidity staking. 
0x tools are mainly meant to serve building DEX's. Additionally, they can also be integrated in various non-trading dApps to help process transactions within blockchain games, marketplaces, or any other products in the market where there is a need in exchange functionality as the secondary component. 0x is an open source protocol, meaning anyone can access smart contracts it offers, copy them, and apply to their application.