Optimistic Rollup

Optimistic Rollups are Layer-2 scaling solutions for Ethereum that allow for faster and cheaper transactions by processing them off-chain and then posting transaction data back to the Ethereum mainnet. Unlike ZK-Rollups, Optimistic Rollups assume that all transactions are valid, hence the term "optimistic." However, they provide a mechanism for validators to challenge and prove fraudulent transactions if they occur. This solution helps to reduce the load on Ethereum’s main chain, improving scalability without compromising on security. Examples of projects using Optimistic Rollups include Optimism and Arbitrum.