The Loopring blockchain protocol covers a specific use case: it combines the utility of decentralized exchanges with the liquidity and user experience of centralized ones. Loopring achieves this by opting to match orders in a centralized way but executing trades on the blockchain. Another signature feature of this protocol is circular trades which eliminate restrictions on pairs and markets. Up to 16 orders can be included and executed in a single circular trade.
More recently, Loopring increased its scope to include payments and value transfers. For these purposes, it is effectively a layer-two scaling solution powered by zero-knowledge cryptography.
The Loopring protocol has implementations on Ethereum, Neo, and Qtum, each with its native token. LRC is the utility token of the Ethereum-based protocol and adheres to the ERC20 standard. LRC tokens can be earned in a process called ring mining which implies matching circular trades of other users.