Rollups are the primary solution which has emerged to increase Ethereums scalability and reduce transaction costs. Transactions are executed off chain where costs are low and speeds are fast, and the rollup operator submits a summary or snapshot of the transaction outcomes to the Ethereum blockchain. This summary includes the new state post-transactions and, depending on the type of rollup, a cryptographic proof (in the case of ZK-Rollups) or a promise of validity (in the case of Optimistic Rollups). This ensures that all the information needed to reconstruct the state of the rollup is available on-chain. Consequently, anyone can challenge or verify the correctness of the state transitions, maintaining the transparent and open nature of blockchain systems. Ethereum is leveraged for its data availability, and as a mechanism to perform dispute resolution.