Optimistic Rollups are a Layer 2 scaling solution for Ethereum, enhancing transaction throughput and reducing fees by processing transactions off-chain. They operate on the principle of optimistic execution, assuming transactions are valid unless proven otherwise by a fraud proof. This approach allows for faster transaction confirmations and significantly lower costs compared to on-chain operations. Optimistic Rollups achieve scalability by aggregating multiple transactions into a single batch, thereby increasing Ethereum’s network capacity while maintaining security through periodic validation on the main Ethereum blockchain.