0x is a decentralized exchange (DEX) aggregator.
It works to find the best price for users looking to swap assets. It does this by pulling liquidity from multiple DEXs on the network.
This saves users from having to search through several exchanges to find the best place to trade an asset. Even if they were up to the task, by the time they found the best price and entered the trade… prices would have likely changed by then.
This makes 0x the one-stop shop to exchange assets on a decentralized network, such as Ethereum.