What are Blobs? Improving Ethereum Scalability

Officially presented at the Ethereum network on March 13, 2024 in the Dencun upgradeblobs are a new type of data storage space designed to create rollups cheaper and more efficient.

The consensus within the Ethereum community is that the best way to scale Ethereum is through rollups, also known as Layer 2 or L2, and that the best way to scale rollups is through the introduction of blobs.

Before blobs, if Ethereum went through a period of congestion, it would also affect the price of transactions on all of its layers 2. The introduction of blobs removes the correlation between Ethereum’s congestion and the cost of transactions on layers 2.

Blobs are a new data structure introduced to Ethereum in EIP-4844, more colloquially referred to as “Proto-danksharding“. EIP stands for Ethereum Improvement Proposal, the process by which Ethereum’s core developers suggest improvements to Ethereum.

Proto-danksharding is the precursor to full-danksharding and lays the foundations by introducing blobs. It does this in the same format in which they will be used when full-danksharding is implemented, in order to simplify the transition to full-danksharding.

Full-danksharding, or simply Danksharding, is an upcoming update to the Ethereum protocol. This represents what Ethereum’s core developers believe is the final step (for now) in making Ethereum a truly scalable blockchain, making transactions faster and cheaper.

Proto-danksharding is a step towards implementing Danksharding: it introduces Danksharding concepts, such as blobs, into Ethereum. Starting with proto-danksharding and introducing blobs, instead of diving straight into full danksharding, reduces the risk created by introducing drastic changes to a network too quickly.

Before blobs, when a layer 2 needed to verify its transactions, it would batch them together and send them to layer 1 (Ethereum) for verification. The problem was that once the data was verified, it would remain stuck on the Ethereum blockchain, taking up block space, forever.

This contributes to state congestion and makes Ethereum more congested, which in turn has also made layer 2s more congested.

With blobs, when data is sent to Layer 1 for verification, it is sent in a blob, short for Binary Large Object. Each blob has 4,096 field elements and can hold up to 32 bytes of data per field element, which equates to about 75 MB per blob. You can think of it as a giant array of data, or… a big blob of data.

Blobs improve on the previous method of data verification in that once data is verified from a blob, it can be deleted. This way, all transaction data for every rollup built on Ethereum does not need to permanently reside on the Ethereum blockchain, taking up valuable space.

Blobs also operate using a separate blob fee market, introducing “blob gas.” Blob gas is independent of gas on the Ethereum mainnet, meaning the only things that use blob gas are the blobs themselves.

Despite the funny names associated with Ethereum’s Dencun upgrade, it’s a serious improvement. Blobs help make Ethereum less congested, and they make rollups cheaper and faster to use.

Indeed, data checked in blobs can be deleted after use. As such, this does not cause state bloat on the Ethereum mainnet. “State bloat” refers to the fact that the more data that Ethereum processes, the more data resides permanently on its blockchain – and the more intensive the maintenance of the “state” of that network becomes.

The separation of the blob gas market from the existing gas market is also a notable improvement. Since blobs have a separate gas market, congestion on Ethereum does not affect them. In the past, if there was a major event on Ethereum, such as a highly anticipated event, NFT At the mint, the congestion caused by this event would leak into Layer 2 and make transactions more expensive there as well. Separating the blob gas markets from traditional Ethereum gas markets removes the correlation between Ethereum network congestion and Layer 2 transaction costs and speeds.

Blobs also make layer 2s much more cost effective. Before blobs, when gas fees were correlated with Ethereum network congestion, the cost of running Layer 2s and Dapps built on them was much higher. Reducing transaction fees allows manufacturers and operators to manage complex smart contracts or products at a fraction of the cost.

Let’s look at the on-chain data of rollup.wtfwe can see that the majority of layer 2s with the most transactions per second are already using blobs.

In a TweeterJesse Pollak, founder of the Layer 2 Base network, revealed that after Dencun, the cost of a simple exchange transaction on Base increased from $0.31 to $0.0005.

However, it hasn’t all been rosy. Blobs have been slower than expected when it comes to publishing transactions to Layer 1. The creation of a new gas market for blobs has successfully decoupled Ethereum’s congestion from the transaction costs of accumulating them, but the gas market itself needs some polishing before it’s all it’s cracked up to be.

In an example in June 2024, blob transactions became more expensive than their predecessor – but this can be seen as a sign that blob adoption is still happening and hopefully as L2s become more efficient in using blobs, more block builders will start accepting blocks that include blobs and as blob capacity increases – costs will come down.

Vitalik Buterin addressed these two questions in a March 2023 blog post published shortly after Dencun was released. In it, Buterin cites two key areas of focus that are needed to continue evolving blobs: “Incrementally increasing blob capacity, eventually realizing the full vision of sample data availability with 16MB per data space slot” and “Improving Tier 2s to make better use of the data space we have.”

So while the blobs have had some growing pains, they were mostly anticipated and solutions are underway.

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