An optimistic rollup batches transactions on a separate execution layer and posts information to Ethereum. The design assumes submitted results are valid unless they are challenged through the protocol’s dispute process.
Sequencers order layer 2 transactions
A sequencer can provide fast confirmations and assemble batches, while the rollup contracts and proof system determine how disputed state transitions are handled. Users should distinguish a fast confirmation from final settlement.
Published data enables independent checking
Rollup participants need enough transaction data to reconstruct state and challenge an invalid claim.
Bridging changes the trust and timing model
Moving assets between mainnet and a rollup uses contracts and messages across layers. Native withdrawals may include a challenge period, while third-party bridges introduce their own liquidity and smart-contract risks.
Fast confirmation and final settlement differ
An application may show a quick layer 2 confirmation before the related batch reaches stronger Ethereum settlement.
Sources
Educational information, not investment advice.