Launched in February 2020, Loopring Exchange describes itself as is the first zkRollup DEX on Ethereum, built atop the Loopring Protocol. The exchange is operated by the Loopring team (which is distributed across China, Belgium, Canada, and the US). It supports the non-custodial trading of ETH and ERC20 tokens. Leveraging zkRollup tech, Loopring Exchange is capable of settling over 2,000 trades per second at a cost as low as $0.0001, without sacrificing 100% Ethereum security guarantees. It claims to be the most scalable DEX on Ethereum.
Loopring is an open protocol for scalable non-custodial exchanges on Ethereum. For more details, please see: https://medium.com/loopring-protocol/looprings-zkrollup-amm-is-live-2f8251cd0fcd