0x Protocol (ZRX) is a decentralized exchange infrastructure designed to facilitate peer-to-peer trading of tokenized assets on the Ethereum blockchain. Launched in 2017 by co-founders Will Warren and Amir Bandeali, the protocol allows developers to integrate decentralized exchange (DEX) functionalities directly into their applications, offering a more modular and flexible trading solution. The primary feature of 0x is its use of off-chain order relays combined with on-chain settlement, which significantly reduces transaction costs and improves efficiency.

The protocol operates on a system of "relayers" who host and manage off-chain order books, providing liquidity by matching buyers and sellers. Once an order is agreed upon, only the final settlement occurs on-chain, minimizing the need for gas fees. This design allows for a scalable and cost-effective approach to trading, compared to traditional on-chain DEX systems.

The native token, ZRX, serves two main purposes within the 0x ecosystem:

1. Governance: ZRX holders can participate in the decentralized governance of the protocol, voting on upgrades and changes to ensure the system evolves to meet user needs.
2. Staking: ZRX tokens are also used to incentivize liquidity providers (relayers) who earn rewards by staking their tokens and contributing to the liquidity pool.

Since its inception, 0x has gone through multiple updates and versions, adding new features such as support for non-fungible tokens (NFTs) and expanding its compatibility across different blockchains. This application-agnostic approach has made 0x a key player in the DeFi (Decentralized Finance) sector, enabling projects to leverage its infrastructure for creating decentralized marketplaces, financial products, and more.