Optimistic Ethereum (OΞ) is a Layer 2 scaling solution for Ethereum. It utilizes a technology known as Optimistic Rollup to provide faster transaction times and lower fees compared to the Ethereum mainnet, while still preserving a high degree of security.
Optimistic Rollups are Layer 2 solutions that execute transactions on a sidechain. The state of this sidechain is periodically “rolled up” and included as a single transaction on the Ethereum mainnet. In essence, Optimistic Ethereum uses the Ethereum network as a kind of court system – most of the time, the sidechain operates independently, but in case of a dispute, the main Ethereum chain is used to arbitrate and settle conflicts.
Optimistic Ethereum gets its name from the Optimistic Rollup technology. It’s “optimistic” because it assumes that most transactions are honest. Only in cases of suspected fraud are transactions closely scrutinized, which saves a lot of computational resources.