Proto-Danksharding is the Ethereum upgrade, specified by EIP-4844, that introduced blob-carrying transactions for publishing rollup data. It went live with Dencun in March 2024 as an initial step toward broader data scaling.
What a blob changes
A rollup can publish batch data in blobs instead of putting all of that data into ordinary transaction calldata. Blob contents are not directly readable by the Ethereum Virtual Machine, although execution can access references and verify related cryptographic proofs. This separates bulk data availability from ordinary contract execution.
Posting a blob incurs a blob-gas charge alongside the transaction’s execution costs. The additional data space can make rollup publication cheaper, but actual user fees depend on demand and the rollup’s processing and pricing. It does not make every Ethereum transaction free or introduce a new fee-payment token.
Temporary availability, separate verification
The protocol requires blob data to remain available for a limited period. That is different from permanent archival storage; operators and other services may retain copies longer. Expiry of the required retention period does not erase every copy or reverse the rollup’s transactions.
A commitment helps check consistency with the published data, not whether the rollup executed its rules correctly. Its proof or challenge mechanism still handles that question. Later upgrades, including PeerDAS in Fusaka, extend blob handling; EIP-4844 alone is not full Danksharding.