What The Fusaka Upgrade Bring to Ethereum

Updated May 2026 | What Does the Fusaka upgrade Bring to Ethereum

TL;DR � Fusaka Upgrade At a Glance

Feature

What It Does

Who Benefits

PeerDAS (EIP-7594)

Nodes verify blob slices instead of full blobs

All Ethereum users, L2 networks

Blob base fee floor (EIP-7918)

Sets a minimum price for blob submissions

ETH holders, validators

Gas limit increase (EIP-7935)

Raises block gas limit from 45M to 60M

Developers, DeFi users

Transaction gas cap (EIP-7825)

Caps per-transaction gas to prevent DoS attacks

Node operators, the network

BPO forks (EIP-7892)

Enables blob capacity to scale without a full hard fork

Layer 2 rollups

Pre-confirmation support

Lets users track when their transaction will be verified

End users, dApp developers

EVM Object Format (EOF) groundwork

Cleaner smart contract structure for faster execution

Solidity developers

Ethereum activated its Fusaka upgrade on December 3, 2025, marking the blockchain's second major hard fork of the year after the Pectra upgrade in May. The Fusaka upgrade brings to Ethereum a sweeping set of changes designed to scale data availability, reduce the cost of operating Layer 2 networks, tighten blockchain security, and make developer tooling more powerful. Unlike Pectra, which delivered visible user-facing changes, Fusaka focuses on deep infrastructure improvements that lay the groundwork for the next decade of Ethereum growth. Everyday users will notice cheaper, faster transactions on Layer 2 networks; validators will carry a lighter data burden; and developers will gain a cleaner execution environment.

Fusaka is short for Fulu-Osaka, a name that combines upgrades to both the consensus layer (Fulu) and execution layer (Osaka). It's 13 Ethereum Improvement Proposals, or EIPs, target three objectives: scaling Layer 2 rollups, improving Layer 1 execution efficiency, and enhancing user and developer experience. This article breaks down everything the Fusaka upgrade brings to Ethereum and explains why it matters for users, investors, and builders alike.

What Is the Fusaka Upgrade? A Short Explanation

Fusaka is the short form for Fulu-Osaka, a code name representing simultaneous changes to both layers of the Ethereum blockchain. Changes in the Fulu section target the Ethereum consensus layer � the part of the network that verifies and finalises transactions � while those in the Osaka section apply to the execution layer, where smart contracts run and transactions are processed. Together, they constitute Ethereum's most infrastructure-focused upgrade since the Merge in 2022.

The Fusaka upgrade builds on a clear progression of previous Ethereum hard forks. The Merge, completed in 2022, transitioned Ethereum from an energy-intensive proof-of-work system to proof-of-stake, slashing energy consumption by roughly 99.9%. The Shapella upgrade in 2023 allowed ETH stakers to withdraw their funds, turning a one-way staking system into a liquid one. The Dencun upgrade in March 2024 introduced "blobs" � a cheaper, temporary data lane for Layer 2 rollups � reducing Layer 2 fees by 90 to 95 percent. The Pectra upgrade in May 2025 increased blob capacity, added account abstraction features via EIP-7702, and revamped validator parameters including a new 2,048 ETH validator cap.

Fusaka now takes that progression significantly further. Its headline feature, PeerDAS, represents a fundamental shift in how nodes handle rollup data, opening the door to 100,000 or more transactions per second across the Ethereum ecosystem � a throughput that surpasses Visa.

What Does the Fusaka Upgrade Bring to Ethereum? Key Features Explained

PeerDAS: The Core of What the Fusaka Upgrade Brings to Ethereum

Peer Data Availability Sampling, known as PeerDAS and defined in EIP-7594, is the headline feature of the Fusaka upgrade and the primary answer to what the Fusaka upgrade brings to Ethereum in terms of scalability. To understand its significance, it helps to understand the problem it solves.

When Layer 2 rollups such as Arbitrum, Optimism, Base, and zkSync post their transaction data to Ethereum mainnet, they do so in the form of blobs � temporary data containers introduced by the Dencun upgrade. Before Fusaka, every full node on the Ethereum network had to download and store every blob in its entirety to verify that the data was available.

This placed significant bandwidth and storage demands on node operators and created a ceiling on how many blobs could be handled without pushing hardware requirements out of reach for ordinary participants.

Slices of Blod Data

PeerDAS changes this model entirely. Instead of downloading full blobs, nodes now only need to verify small, randomly sampled slices of blob data. Using probabilistic guarantees, the network can confirm that a blob is fully available without any single node holding the whole thing.

Each node stores roughly one-eighth of the data contained in each blob, and nodes can reconstruct missing portions when needed. The result is a dramatic reduction in per-node storage and bandwidth load while simultaneously allowing the network to support a far greater volume of blob data.

"PeerDAS' importance was such that, during the initial development of the Fusaka upgrade, any feature that carried a risk of delaying the fork was deprioritised and removed from scope," said Gabriel Trintinalia, an Ethereum core developer and engineer at Consensys. "The Fusaka upgrade really shows that Ethereum is serious about making mainnet faster."

PeerDAS is also Ethereum's first step toward full danksharding, which will eventually enable orders of magnitude more data throughput at vastly lower transaction costs. By introducing PeerDAS now, Fusaka lays the essential groundwork for that longer-term scaling milestone.

A New Blob Fee Structure and What It Means for Ethereum

One of the more economically significant things the Fusaka upgrade brings to Ethereum is a mandatory minimum base fee for blobs, introduced through EIP-7918. Before Fusaka, blob fees could drop to near-zero during quiet periods on the network � a quirk that had emerged following the Dencun upgrade. When transaction volume was low, Layer 2 rollups could post data to Ethereum mainnet essentially for free.

While that might sound beneficial for users on the surface, it weakened Ethereum's fee burn mechanism and severed the link between real network usage and ETH's economic value accrual. The reserve price introduced by EIP-7918 ensures that when the blob fee falls below a proportional minimum, the fee-adjustment algorithm treats the block as over-target and stops pushing the fee toward zero.

Beyond pricing, the Fusaka upgrade also introduces Blob Parameter Only forks, defined in EIP-7892. These are lightweight, config-only upgrades that allow the network to raise blob targets and maximums on a rolling schedule � without waiting for a full named hard fork. Immediately after the main Fusaka activation on December 3, 2025, two BPO rounds went live: BPO1 raised the per-block blob target to 10 and maximum to 15, and BPO2 further increased those figures to 14 and 21. This gives rollup teams clear, predictable visibility into future capacity, something the Ethereum ecosystem had been calling for.

Gas Limit Increase and Transaction Gas Cap: What the Fusaka Upgrade Brings to Ethereum's Execution Capacity

Another significant area of what the Fusaka upgrade brings to Ethereum is at the execution layer, where two complementary changes work together to boost throughput while preserving security.

EIP-7935 raises Ethereum's default block gas limit from 45 million to 60 million, with a long-term research target of up to 150 million. The gas limit had been largely static since the Merge in 2022, with only minor adjustments, and increasing it now allows each block to carry more execution data, smart contract interactions, and rollup submissions. More transactions per block means faster service and lower fees during periods of high demand.

To ensure that this capacity increase does not open the network to abuse, Fusaka pairs the gas limit increase with EIP-7825, a per-transaction gas cap. Before this change, a single large transaction could theoretically consume an entire block's gas budget, making the network vulnerable to denial-of-service attacks where one transaction starves out thousands of others.

The cap ensures that no single transaction can dominate a block, even as overall throughput grows. The upgrade also caps block size on the execution layer at 10 MB, a further safeguard against oversized blocks overwhelming node operators.

Together, these two EIPs allow Ethereum to scale meaningfully at Layer 1 without compromising decentralisation or security � a balance that Ethereum core developers have worked to maintain throughout the upgrade roadmap.

Pre-Confirmation Support

The Fusaka upgrade also introduces support for transaction pre-confirmations, a feature that enables developers and users to see in advance which validator is scheduled to process a given transaction and when. This gives users greater certainty about when their transactions will be included in a block, reducing the uncertainty that has long been a friction point in blockchain UX.

For developers building consumer-facing applications, pre-confirmation support opens the door to more responsive user experiences � particularly in gaming, payments, and decentralised finance, where transaction timing has a direct impact on product quality.

EVM Object Format and Developer Tooling Improvements

On the developer side, one of the underappreciated things the Fusaka upgrade brings to Ethereum is foundational work on the EVM Object Format, or EOF. EOF restructures how smart contracts are stored and executed within the Ethereum Virtual Machine by cleanly separating code from data. This makes contracts easier to validate, analyse, and optimise at the compiler level.

For Solidity developers, EOF means fewer unexpected edge cases, faster contract execution, and a more predictable programming environment. While Fusaka does not complete the full EOF migration, it introduces critical groundwork that will smooth future upgrades.

Combined with optimisations to the ModExp precompile � a component used in complex cryptographic operations � and improvements to network-layer efficiency via EIP-7642, Fusaka makes the Ethereum development environment meaningfully more capable.

How Does the Fusaka Upgrade Affect Ethereum Users?

Most Ethereum users will not need to take any action following the Fusaka upgrade. Node operators updated their execution and consensus layer clients; for everyone else, the network continues to operate normally.

In practical terms, the biggest benefits flow to users of Layer 2 networks. Rollups benefit directly from PeerDAS, the new blob fee structure, and the gas limit increase. The combined effect is faster transaction settlement and lower fees on networks like Arbitrum, Optimism, Base, and Scroll � regardless of overall demand on the Ethereum mainnet.

For investors and ETH holders, the introduction of a blob base fee floor is the most consequential economic change. By ensuring that blob fees cannot fall to zero during low-activity periods, the upgrade strengthens the ETH fee burn mechanism and tightens the relationship between Ethereum's real-world usage and the value of ETH.

For enterprises and traditional financial institutions, Fusaka is also drawing attention. Fidelity Digital Assets published a report in late November 2025 describing the Fusaka upgrade as a decisive step toward a more strategically aligned and economically coherent roadmap for Ethereum.

The upgrade reinforces Ethereum's positioning as a high-capacity settlement and data engine � a role that institutions evaluating blockchain infrastructure increasingly care about.

The Fusaka Upgrade in Ethereum's Long-Term Roadmap

Fusaka sits within Ethereum's broader development roadmap, commonly summarised as the Merge, Surge, Verge, Purge, and Splurge. The Surge phase, focused on scaling Ethereum through rollups and better data availability, is where Fusaka makes its most direct contribution. PeerDAS is Ethereum's introduction to danksharding � the full vision of which would allow for massive data throughput increases while keeping node requirements accessible.

The Verge and Purge phases, focused on lighter clients and pruning historical data, are also advanced by Fusaka. The upgrade introduces partial history expiry support, meaning Ethereum clients no longer need to store all historical chain data indefinitely.

Groundwork for Verkle Trees � a next-generation state structure that will reduce proof sizes and improve lightweight client performance � is also included, though the full transition is planned for a later upgrade.

Following Fusaka, the next planned upgrade is Glamsterdam, expected in the first half of 2026. Glamsterdam is set to introduce enshrined proposer-builder separation (ePBS), which will harden the MEV supply chain by separating block building and proposing at the protocol level, and block-level access lists (BALs), which improve censorship resistance. Ethereum core developers are now targeting a twice-a-year upgrade cadence, a pace that reflects the ecosystem's growing operational maturity.

Frequently Asked Questions About the Fusaka Upgrade

What does the Fusaka upgrade bring to Ethereum in simple terms?

Fusaka makes Ethereum faster, cheaper, and more secure � especially for users of Layer 2 networks. Its most important change, PeerDAS, reduces how much data each node must store, allowing the network to handle far more rollup transactions without raising hardware requirements. Other changes increase the gas limit per block, introduce a minimum fee for blob data, and improve smart contract execution for developers.

When did the Fusaka upgrade go live on Ethereum?

The Fusaka upgrade activated on Ethereum mainnet on December 3, 2025, at 21:49 UTC � at slot 13,164,544. It was the second major Ethereum hard fork of 2025, following the Pectra upgrade in May. The upgrade had previously been validated on the Hoodi, Holesky, and Sepolia testnets.

Do Ethereum users need to do anything because of Fusaka?

No. The Fusaka upgrade does not require any action from regular Ethereum users. Node operators and validators needed to update their clients, but for everyone else the network continues to function normally. Users of Layer 2 networks will gradually see lower fees and faster finality as rollup teams take advantage of the new capabilities.

How does PeerDAS improve Ethereum scalability?

PeerDAS allows Ethereum nodes to verify blob data by sampling small slices rather than downloading entire blobs. This dramatically reduces per-node storage and bandwidth requirements, allowing the network to support a much larger number of blobs � and therefore much greater Layer 2 throughput � without increasing the hardware demands placed on validators and full node operators.

What is the blob base fee and why does it matter?

Before Fusaka, blob fees could fall to near-zero during quiet periods on the network, which weakened Ethereum's fee burn mechanism and reduced ETH's economic value accrual. EIP-7918 introduces a minimum reserve price for blob submissions. When actual fees fall below this floor, the protocol treats blocks as over-target and prevents fees from dropping further, ensuring that Ethereum captures economic value from Layer 2 activity even during low-demand periods.

What comes after the Fusaka upgrade?

The next named upgrade after Fusaka is Glamsterdam, expected in the first half of 2026. Its two headline features are enshrined proposer-builder separation (ePBS), which improves MEV transparency and censorship resistance, and block-level access lists (BALs). Ethereum developers are targeting a twice-a-year upgrade schedule, meaning Glamsterdam could arrive as early as mid-2026.

Will the Fusaka upgrade affect the price of ETH?

No upgrade directly guarantees a price movement, and historically, Ethereum upgrades have not reliably triggered immediate price changes. That said, the introduction of a blob base fee floor and the overall strengthening of Ethereum's value capture from Layer 2 activity are constructive for ETH over time.

Bitwise Asset Management noted in a December 2025 report that Fusaka is the kind of unflashy infrastructure change markets tend to overlook in the short term and credit later for making the network sturdier and more investable.

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