Optimistic and ZK rollups, both submit data to Ethereum or similar chain, but why do optimistic rollups take longer time then zk rollups? What's the core difference that causes this time difference?

1 Answer 1


In a zk rollup, the sequencer submits a batch of transactions and a proof that the new state root was computed correctly.

In optimistic rollups, the sequencer only submits the batch of transactions and the proposed new state root. The new root is assumed to be valid unless proved otherwise. The 1 week delay is necessary so that other participants have time to challenge the sequencer, in case the new root is incorrect. Such a dispute is then settled on the main chain.

You can learn more about how such fraud proofs work here.

  • does zkrollup submit proof first then batch of transactions, or vice versa. how does solidity code work in this submit and batch transactions ?
    – aakash4dev
    Commented Feb 9, 2023 at 15:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.