GlossaryAdvanced
Data Availability
Whether the data needed to verify a blockchain's state is actually accessible to the network.
Data availability refers to whether the underlying transaction data needed to verify a blockchain's current state is actually published and accessible, not just a summary or proof of it.
This matters especially for Layer 2 rollups: if transaction data isn't genuinely available, independently reconstructing account balances or challenging an incorrect state becomes difficult or impossible.
Examples
- A rollup posting full transaction data to its base chain is prioritizing data availability over cost savings.
- Data availability is a core design consideration distinguishing different Layer 2 scaling approaches.