Ethereum has officially launched Fusaka, the seventeenth major upgrade in its history and one of the most important steps for the network’s long-term scalability.
What makes Fusaka significant is that it enhances both Ethereum itself and the entire Layer 2 ecosystem built upon it.
As Ethereum continues to support more users and more activity, the network must reduce its storage burden, improve efficiency and provide a smoother experience for people interacting with decentralised applications. Fusaka addresses these needs directly.
It brings changes designed to make Ethereum lighter, faster, more flexible and easier to use, preparing it for years of continued growth.
What is the Fusaka Upgrade?
Fusaka is an update that applies to both major parts of the Ethereum system: the execution layer, which processes transactions and smart contracts, and the consensus layer, which keeps the network in agreement about the state of the blockchain.
By affecting both sides, Fusaka strengthens the foundation that every application and Layer 2 network relies on.
One of the biggest changes in Fusaka relates to how much old data Ethereum keeps. Over time, Ethereum nodes accumulate large amounts of historical information.
The older this history becomes, the less useful it is for day-to-day operations, yet it still takes up a large amount of storage.
Fusaka makes history expiry a requirement for clients, which means nodes can safely delete parts of the past that are no longer needed. This reduces data bloat and keeps the cost of running a node manageable for more people.
Another key element of Fusaka is the change in gas structure. Gas is the unit that measures how much work a transaction requires. Before Fusaka, a single large transaction could theoretically consume most of a block, which could delay other activity.
Fusaka introduces a maximum limit for each transaction so that no single operation can overwhelm the system. At the same time, the upgrade encourages clients to increase the amount of work that can be included in each block overall.
In simpler terms, each transaction cannot be excessively heavy, but the network as a whole can now process more transactions at once. This combination strengthens reliability while expanding capacity.
Fusaka also brings improvements to the user’s experience. A new feature now allows Ethereum to verify secp256r1 signatures. While the name sounds technical, its impact is very practical.
This is the same signature standard used by passkeys and device-level authentication on smartphones and laptops. It means people can log in or sign actions using methods they already understand, instead of relying on seed phrases or unfamiliar tools.
This change helps Ethereum feel closer to the experience offered by everyday apps while still preserving decentralised security.
The final major component of Fusaka is the upgrade to blob handling. Blobs are special data packages used by Layer 2 networks when they publish their transaction data to Ethereum.
Fusaka introduces PeerDAS, a new system that dramatically reduces the amount of blob data each node must download. It also creates new flexibility for increasing blob capacity whenever needed. These changes have a large effect on how well Layer 2 networks can scale.
The Benefits of the Upgrades for the Ethereum L1
The first and most visible benefit for Ethereum’s main layer is the reduction in storage requirements.
Without history expiry, nodes would accumulate more and more old data, eventually making the system burdensome to run.
By allowing clients to drop older history safely, Fusaka keeps node storage light and prevents unnecessary growth. This ensures that running a node remains accessible, which is crucial for decentralisation.
Fusaka also improves the balance between individual transactions and the total workload of each block.
By placing a limit on the maximum gas a single transaction can use, the network avoids situations where one unusually large operation causes delays. This strengthens protection against potential congestion.
Meanwhile, the increased block gas target allows the system to process more activity in the same amount of time. The outcome is a smoother experience with more space for users and applications.
Beyond these adjustments, Fusaka updates the cost model for certain types of mathematical operations used in smart contracts.
These operations, especially those involving very large numbers, could previously have been underestimated in their true computational cost.
Fusaka corrects this so that contracts pay a more accurate fee for the resources they use. This helps keep block processing times consistent and lowers the risk of slowdowns.
The introduction of the CLZ opcode also modernises the execution environment. It provides a simple way for smart contracts to count leading zeros in a piece of data.
While this may seem small, it reduces the amount of manual code developers must write and allows some contract functions to run more efficiently.
On the consensus side, deterministic proposer lookahead gives validators more visibility into upcoming responsibilities.
Validators can now see further into the schedule, which helps improve planning and enables features such as preconfirmations. This transparency supports a smoother and more predictable network.
Fusaka also introduces the eth_config RPC call, which provides a clear snapshot of configuration settings for the current and upcoming forks. This helps node operators detect misconfigurations before they cause issues and supports better coordination for future upgrades.
The Benefits for the Ethereum L2 Ecosystem
Fusaka has an even greater impact on Layer 2 networks, which depend on Ethereum to publish their transaction data securely and efficiently. To understand this, it is helpful to clarify what blobs are, since they are central to the improvements in this upgrade.
A blob is a temporary data container used by Layer 2 networks when they post their batch data to Ethereum.
Unlike normal transaction data, blobs are not stored permanently. They exist only long enough for the network to ensure the data is available for verification, after which they can be safely discarded. This keeps Ethereum from accumulating unnecessary storage while still allowing rollups to operate with strong security guarantees.
Blobs also cost significantly less than storing equivalent data using traditional methods, which is why they are essential for keeping Layer 2 transaction fees low.
Before Fusaka, every node on Ethereum had to download every blob in full. As Layer 2 networks grew, this created practical limits on how much blob data the system could support.
Fusaka solves this with PeerDAS. Instead of downloading entire blobs, each node now stores only a fraction of the data.
This lowers bandwidth requirements and makes the system far more efficient. It also unlocks room for Ethereum to support up to eight times more blob capacity in the future.
In addition to PeerDAS, Fusaka introduces Blob Parameter Only forks. These allow Ethereum clients to increase blob capacity quickly whenever Layer 2 networks need more space.
The change no longer requires a full hard fork, which means the ecosystem can respond faster to growth. This flexibility ensures that Layer 2 networks are not limited by delayed upgrade schedules.
Blob fees also become more predictable with Fusaka. Previously, blob fees could fall to extremely low levels during certain network conditions, which made the fee market less reliable.
Fusaka prevents blob fees from collapsing in this manner, ensuring that prices reflect real usage and keep the network stable.
Overall, these improvements ensure that Layer 2 networks can scale smoothly, process more data and offer more predictable fees for users. As the majority of transactions now take place on rollups, this is a major step forward for the entire ecosystem.
Conclusion
Fusaka marks a significant advancement for Ethereum and strengthens the foundation of both the main chain and the Layer 2 ecosystem.
By reducing storage requirements, improving block capacity, stabilising costs and introducing more familiar authentication methods, the upgrade makes Ethereum more efficient and more approachable.
At the same time, the improvements to blob handling and data availability provide Layer 2 networks with the tools they need to continue scaling.
Together, these changes prepare Ethereum for a future with higher activity, broader adoption and more demanding applications, all while keeping the network accessible and secure for the long term.