Blob Transaction

Overview

Meaning and scope

A blob transaction is an Ethereum transaction type introduced by EIP-4844 that carries commitments to temporary data blobs used mainly by rollups for lower-cost data availability. The transaction references cryptographic commitments to data blobs that are propagated separately from ordinary execution calldata and retained only temporarily.

Mechanism and operation

Blob transactions, also called type-3 transactions, let Ethereum rollups publish large batches of data in a form that is cheaper than permanent execution calldata. The transaction contains commitments to blobs, while the blob data is propagated and stored by the consensus layer for a limited retention period. This design separates temporary data availability from ordinary execution data. A transaction pays ordinary execution gas and a separate blob fee based on blob demand. The mechanism supports rollup scaling because users and verifiers can obtain the data needed to reconstruct layer-2 state during the availability window without forcing every byte to remain permanently in Ethereum’s execution state.

Practical payment example

A rollup batches transaction data into an Ethereum blob transaction. Its monitor associates the blob commitment with the published batch while recognizing that blob content is not directly readable by EVM contracts.

Operational checks

A blob transaction is not a transaction that sends a “blob token,” and it is not a generic name for any large blockchain transaction. Blob transactions introduced a separate data-availability resource and fee market. They still pay ordinary execution gas for the transaction envelope and any EVM work, while blob gas is priced independently according to network demand.

Distinctions and limits

The Ethereum Virtual Machine cannot directly read blob contents. Smart contracts can access a blob commitment-related value but not use blobs as permanent contract storage.

Related reading

Related definitions: transaction, consensus layer.