EIP-4844

EIP-4844 is the Ethereum Improvement Proposal that specifies proto-danksharding: the precise rules for blob-carrying transactions and a separate blob-gas market. It went live in the Dencun hard fork on 13 March 2024 and is the single most impactful scaling change Ethereum has shipped for rollups, because it gave Layer 2s a dedicated, cheap data channel rather than forcing them to buy expensive calldata. Where danksharding is the broad vision, EIP-4844 is the exact, deployed specification that started it.

Its concrete contributions are a bundle of new primitives. It defines the type-3 transaction that carries blob commitments; the blob format (4096 BLS12-381 field elements per blob); KZG commitments and versioned blob hashes; a point-evaluation precompile (at address 0x0A) so contracts can verify claims about blob contents; the BLOBHASH opcode for reading a transaction's blob commitments; and an independent blob-gas market with its own exponentially-adjusting base fee. It also fixed the launch capacity at a target of 3 and a cap of 6 blobs per block, each blob 128 KiB and pruned after about 18 days.

The economic design is what made it land so well. Because blob gas is priced separately from execution gas, the two fee markets do not crowd each other out, and because the blob base fee adjusts toward a target like EIP-1559, costs stay low while demand is below capacity — which it usually is, given only a few blobs per block. The result was an order-of-magnitude drop in rollup data-posting costs overnight, and the proposal was intentionally written so its interfaces stay stable as later upgrades raise blob counts and add data availability sampling on the way to full danksharding.