Data Availability

Data availability is the requirement that transaction data behind a rollup batch must be published where anyone can download and verify it. Without accessible data, even a perfect proof system cannot help users reconstruct L2 state or force an exit through the L1 contract.

If a sequencer censors you or goes offline, published data lets you submit your transaction directly to the L1 rollup contract — a forced inclusion mechanism that does not depend on the operator cooperating.

Ethereum's scaling roadmap treats data availability as a first-class problem. Cheaper DA on L1 directly translates into cheaper L2 transactions, which is why blob space and future danksharding upgrades matter so much.