Optimistic Rollups (ORUs) are layer 2 solution technology helps to scale Ethereum smart contract and Dapps. Optimistic Rollups can scale the Ethereum protocol up to 100 to 2000 transactions per second (TPS). The major advantage it has over other scaling solutions is that it enables Turing-complete smart contracts on layer 2 using Optimistic Virtual Machine (OVM). Thus reducing user transaction cost.