IDEX is the first Ethereum based decentralized smart contract exchange to support real-time trading. It claims to be the most advanced Ethereum DEX. It supports limit and market orders, gas-free cancels, and the ability to fill many trades at once.
The exchange consists of a smart contract, a trading engine, and a “transaction processing arbiter”.The smart contract is responsible for storing all assets and executing trade settlement. The user has to verify all trades using the user’s private keys.