Comparing dYdX and ZigZag Protocol

Decentralized exchanges are one of the most natural applications of decentralized finance. The long-term vision is that elimination of custodial overhead, reduction of execution costs, and universal access can ultimately make DEXs more competitive and cost-effective than centralized counterparts. 

Some of the earliest DEX protocols (e.g., EtherDelta, IDEX) were based on simple traditional order book models. In the context of a public blockchain, a limit order is simply a signed message attached to escrowed funds. It follows that an order book protocol is simply a maintainer of a database of signed limit orders.