Ethereum blob explorer: read the rollup data layer

If you have ever opened a block on Etherscan and seen a line such as “Blob gas used: 2,621,440”, you have met the part of Ethereum most users never touch directly. An Ethereum blob explorer makes that layer readable: which rollup posted which blob, how much it paid, and whether the data is still available. Blobs are the reason a swap on Base or Arbitrum costs a cent or less in 2026, so they are worth understanding even if you never send one yourself.

Below we cover what blobs are, how the separate blob gas market works, how the Pectra and Fusaka upgrades changed capacity, who actually uses the space, and how to read blob data in Blobscan, Etherscan and Blockscout. All numbers were checked on 24 September 2026.

What blobs are: EIP-4844 in plain words

Rollups execute transactions off-chain and then post their data back to Ethereum so anyone can rebuild their state. Before March 2024 they did this with calldata, the same byte field that normal transactions use to call contracts. Calldata is stored by every node forever and priced like any other gas, which made rollup fees swing with mainnet congestion.

EIP-4844, also called proto-danksharding, went live with the Dencun upgrade on 13 March 2024. It added a new kind of attachment, the blob. A blob is exactly 4,096 field elements of 32 bytes, which is 131,072 bytes or 128 KiB. It rides alongside a block on the consensus layer rather than inside it. The execution layer, where the EVM lives, only ever sees a short versioned hash derived from a KZG commitment to the blob. You will recognise these hashes in explorers because they start with 0x01, the version byte.

That split is the whole trick. Smart contracts cannot read blob contents; they can only check the hash (through the BLOBHASH opcode) and verify small proofs about the data with a precompile. In exchange, nodes do not keep blobs forever. They must serve them for 4,096 epochs, about 18 days, which is plenty of time for anyone to download the data and challenge or verify a rollup. After that the bytes can be pruned, while the commitment stays in the chain history permanently.

The blob gas market, separate from execution gas

Each blob consumes 131,072 units of blob gas (2¹⁷, one per byte). Blob gas has its own base fee, priced separately from the execution base fee you know from our Ethereum gas tracker. The logic mirrors EIP-1559: when blocks carry more blobs than the target, the blob base fee rises exponentially; when they carry fewer, it falls. The fee is burnt, just like the execution base fee.

A real example makes the scale clear. Block 26,046,167 (24 September 2026, 08:35 UTC) carried 20 blobs, so 2,621,440 blob gas, at a blob gas price of 8,792,615 wei, roughly 0.0088 gwei. Multiply it out and each blob cost about 0.0000012 ETH, a fraction of a US cent, to post 128 KiB of data. Blobscan also estimates what each blob would have cost as calldata, and across all rollup blobs since Dencun its averages put blobs at roughly one fifteenth of the calldata price. That gap is why rollups moved almost entirely to blobs within weeks of Dencun.

Early on, the blob base fee could sink all the way to 1 wei when demand was below target, which made the market sluggish when demand suddenly returned. Fusaka added EIP-7918, which ties a reserve price for blobs to the execution base fee, so blob fees can no longer collapse to effectively zero while the rest of the chain is busy. A blob transaction still pays normal execution gas too: sending a type-3 transaction costs at least the usual 21,000 gas plus whatever the rollup’s inbox contract does.

How Pectra and Fusaka changed blob capacity

Blob space has grown in steps, and the step size matters because the target is what pulls the price down. Here is the history, with target and maximum blobs per block:

1. 13 Mar 2024

   Dencun: blobs arrive 3 / 6

   EIP-4844 goes live with a target of 3 and a maximum of 6 blobs per block.

2. 7 May 2025

   Pectra doubles the target 6 / 9

   EIP-7691 raises capacity to a target of 6 and a maximum of 9, and retunes how quickly the blob fee moves.

3. 3 Dec 2025

   Fusaka ships PeerDAS PeerDAS

   With PeerDAS (EIP-7594), nodes sample columns of blob data instead of downloading every blob. It also caps a single transaction at 6 blobs and introduces blob-parameter-only (BPO) forks.

4. 9 Dec 2025

   BPO1 10 / 15

   The first parameter-only fork lifts the target to 10 and the maximum to 15, with no new features attached.

5. 7 Jan 2026

   BPO2 14 / 21

   The second BPO fork raises the target to 14 and the maximum to 21, the values in force in September 2026.

The BPO mechanism (EIP-7892) is quietly one of the most important changes. Instead of waiting for a named upgrade every year, core developers can schedule a fork that changes nothing but the blob numbers. PeerDAS is what makes further increases safe: because each node only stores a slice of the data, capacity can in theory grow several-fold without asking home stakers for much more bandwidth. Future BPO steps are expected, but no further values were locked in when we wrote this, so be sceptical of any specific number you see quoted for later in 2026.

Which rollups post blobs

Blobscan labels blob senders it can identify, and its counters on 24 September 2026 tell a clear story. Out of roughly 22.4 million blobs posted since Dencun, Base alone accounts for about 8.2 million, well over a third. World Chain and Arbitrum follow with around 2.3 and 2.2 million each, then OP Mainnet with about 1.4 million. Taiko, Unichain, Soneium, Blast, Scroll, Starknet, Linea and dozens of smaller chains make up much of the rest, and a few million blobs come from senders Blobscan has not labelled.

Two details are useful when you read these numbers. First, rollups batch differently. Base often posts several blobs in one transaction, while chains such as Taiko send closer to one blob per transaction. Second, a full blob is not always full of data: rollups pay for the whole 128 KiB even if they use less, so blob usage efficiency varies a lot between chains. If you want to follow an individual rollup’s posting pattern, our overview of layer 2 explorers lists the network explorers that show the L2 side of each batch.

Blob explorers compared: Blobscan, Etherscan and Blockscout

Blobscan: the specialist

Blobscan was built for blobs and nothing else. Its front page shows recent blocks with blob counts, blob gas prices and the rollups behind each transaction. Click a blob and you get its versioned hash, KZG commitment, size, the transaction that carried it and, crucially, the raw data even after the network has pruned it, because Blobscan keeps its own copies in several storage backends. The code is open source on GitHub, and besides mainnet there are instances for the Sepolia and Hoodi testnets.

For developers, the best part is the public API at api.blobscan.com, which needs no key. A request to /stats/overall returns global and per-rollup totals, and /blocks?ps=1 gives you the latest block with its blobs. It is a friendly way to add blob data to a dashboard. For a broader look at free data sources, see our Ethereum explorer API guide.

Etherscan blob pages

Etherscan added blob support quickly after Dencun. A dedicated blob transactions list shows each type-3 transaction with its blob count, blob gas price and the fee paid, and every blob has its own detail page keyed by the versioned hash. Block pages show blob gas used and the excess blob gas that drives pricing. If you already use Etherscan daily, this is enough for most questions; our Etherscan review covers the rest of the feature set.

Blockscout blob views

The Blockscout explorer at eth.blockscout.com has a blob transactions tab, blob detail pages that show the raw blob bytes while they are still available. Its API exposes the same data without a key, which is why our own live Ethereum explorer can show blob counts and blob gas on block pages. More in our Blockscout review.

One more angle: because blobs live on the consensus layer, beacon chain explorers such as beaconcha.in show blob counts per slot. That is useful when you are checking a validator’s blocks, as described in our beacon chain explorer guide.

Reading a type-3 blob transaction

Blob-carrying transactions are type 3 in Ethereum’s numbering (type 2 is a normal EIP-1559 transaction, type 4 the EIP-7702 set-code type). In an explorer, they look like a regular transaction with a few extra fields. max_fee_per_blob_gas is the ceiling the sender will pay per unit of blob gas. blob_versioned_hashes lists one hash per attached blob, up to six. The receipt adds blob gas used and blob gas price, and many explorers show a “blob fee” that multiplies the two.

A type-3 transaction must have a to address, so it can never deploy a contract, and in practice the recipient is almost always a rollup’s batch inbox. The sender is the rollup’s batcher, an address that does this all day. Open one of Base’s batcher transactions and you will see it post several blobs every few blocks, with the blob fee far below the ordinary execution fee on the same transaction. Our transaction explorer guide explains the ordinary fields around them.

How to check that a rollup posted its data

Say you bridged funds to an L2 and want to see its data land on Ethereum. Find the rollup’s batcher address in its documentation or on Blobscan’s rollup filter. Open that address in any explorer and look at its latest type-3 transactions: you should see a new one every few minutes, each carrying one or more blobs. Blobscan will show the blob sizes and the price paid. On the L2 explorer, the batch or “L1 submission” details point back to the same mainnet transaction hash. If the batcher has gone silent for hours, that is worth knowing, and it is exactly the kind of signal risk trackers watch.

Blobs are still young, and the explorers are still catching up with PeerDAS-era details such as column sampling. For everyday questions, the three tools above are all you need. For the bigger picture of how Ethereum is scaling, ethereum.org’s danksharding roadmap page is a good next read, and if you are ranking explorers for your own use, our best Ethereum explorers ranking compares them across every feature, not only blobs.