Optimistic Approach Rollups

Optimistic Rollups are Layer 2 scaling solutions for the Ethereum blockchain that relies on off-chain computations to record transactions outside of the Ethereum mainnet, thereby reducing the load on the mainnet while improving scalability. In Optimistic Rollups, transactions are written to the Ethereum main chain transaction data, which further optimizes it by reducing gas costs.

Between the two types of rollups - zero knowledge (ZK) rollups and optimistic rollups - the main difference is the method of verification. Optimistic rollups assume that all transactions are valid and batches can be submitted without requiring a large amount of computational power, which obviously improves scalability significantly. However, they include a time limit for disputing the transaction, during which anyone and everyone is given the legitimacy to dispute the data contained in a batch. Once a fraudulent or incorrect transaction is discovered, the rollup performs what is known as a proof of fraud and performs the correct transaction calculation using the data available at Layer 1. The incentive to process only legitimate transaction data is provided by requiring ETH to initiate a transaction. So if you perform the task well and conscientiously, you get a reward for using ETH. However, if a sequencer submits a false or fraudulent transaction to the Ethereum main chain, the stake is reduced.