Optimism Optimistic Rollup

Optimism is a Layer 2 scaling solution for Ethereum using Optimistic Rollups. Transactions execute on Optimism chain (much cheaper, faster). Periodically, transactions are batched and posted to Ethereum mainnet. If any transaction is invalid, a "fault proof" lets users challenge it. Simplicity: assume all transactions valid (optimistic), prove otherwise if needed. Result: 100x lower fees ($0.01 vs $1 per transaction), 4000 TPS vs 15 TPS on mainnet, while remaining secured by Ethereum.