Optimistic Rollup
An optimistic rollup executes transactions off-chain and posts the results to Ethereum, *assuming* they're valid — "innocent until proven guilty." Anyone w
An optimistic rollup executes transactions off-chain and posts the results to Ethereum, *assuming* they’re valid — “innocent until proven guilty.” Anyone watching can submit a fraud proof during a week-long challenge window; a successful challenge reverts the batch and slashes the cheater.
Why it matters
Optimistic rollups (Arbitrum, Optimism) scaled Ethereum years before ZK tech matured, and the model works. The decentralization caveats: a centralized sequencer orders transactions today, and the week-long withdrawal window exists precisely because security depends on vigilant challengers.