All terms
The guarantee that transaction data was actually published for anyone to read.
A rollup is only secure if its data is available. If the operator posts a state root but hides the underlying transactions, nobody can verify or challenge it, and nobody can reconstruct their balances.
This is the largest cost a rollup faces, which is why dedicated data availability layers exist.
Celestia and EigenDA sell cheap data availability so rollups can cut their biggest expense.
That data availability is the same as data storage. The guarantee is that the data was published so anyone could download it, not that anyone kept it forever. A rollup that cannot prove publication cannot prove its state, which is why this is a separate problem.
Common questions
Why does data availability matter to me?
What is a data availability layer?
Where this comes up on the site
The guides that actually use this word, rather than a list of everything we have written.
Where to go next
More technology terms
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