Ethereum Fusaka Upgrade: All You Need to Know

The most awaited blockchain upgrade of the year successfully rolled out earlier this month: the crypto world's leading smart contract platform, Ethereum, just ushered in its pivotal transformation to date, the Fusaka Upgrade.

With 12 critical Ethereum Improvement Proposals (EIPs), the Fusaka Upgrade introduces core technical improvements, monetary system upgrades, improved user experience, enhanced security, reduced validator requirements, and more. These breakthrough developments are a big leap towards Ethereum's vision of creating a decentralised, yet scalable and secure, global settlement platform that works like a "World Computer". The Fusaka Upgrade is making all of this and more possible. Let's find out all there is to know about the Fusaka Upgrade and how it will reshape the Ethereum ecosystem.

What is the Ethereum Fusaka Upgrade?

The Fusaka Upgrade is a comprehensive network upgrade deployed across the Ethereum network. A hard fork (an upgrade that isn't backwards-compatible), Ethereum's Fusaka Upgrade rolled out on December 05, 2025, following successful testnet trials and a $2 million bug bounty program to ensure network stability.

The Fusaka Upgrade, the largest bundled network upgrade for Ethereum since 2022, aims to improve the network's overall functionality. From boosting network security to introducing more efficient data models and establishing the network's core economic structure, the Fusaka upgrade does plenty for Ethereum.

Effectively building on the Pectra upgrade, Fusaka is Ethereum's second major hard fork in 2025. This upgrade aims to lower transaction fees and improve layer-2 data processing. From a user experience perspective, Fusaka takes Ethereum to the next level in creating a user-friendly network.

Fusaka combines the two words Fulu (for the consensus layer, named after the star) and Osaka (for the execution layer, named after the Japanese city), which refers to two simultaneous Ethereum hard forks - one on the execution layer and one on the consensus layer. The execution layer handles transactions and smart contract operations, while the consensus layer verifies, finalises, and secures them.

Read on to get an in-depth insight into everything Ethereum's most-awaited upgrade brings to the table.

Key Features of Fusaka Upgrade

Fusaka includes 12 major Ethereum Improvement Proposals (EIPs). Here are some of the key features of the Fusaka Upgrade:

1. PeerDAS

This is the main feature of the Fusaka Upgrade, which revolutionises how Ethereum handles data.

Currently, Ethereum's layer-2 networks, such as Arbitrum and Optimism, post all their transaction data to the main Ethereum blockchain for validation. Validators need to download the entire dataset for validation, which requires expensive hardware and high bandwidth to download massive datasets simultaneously.

PeerDAS, or Peer Data Availability Sampling, changes this. This efficient data-processing method enables validators to download a small sample of a dataset rather than the entire dataset for verification. This feature slashes bandwidth requirements by up to 85%, making data processing and validation faster and cheaper.

Around 12.5% of a data set is sampled randomly and downloaded. Using mathematical techniques called erasure coding, which add redundant data to the dataset (something like a backup system or data cookies), the network reconstructs the complete data from the pieces downloaded.

PeerDAS benefits Ethereum's layer-2 solutions, such as Arbitrum, Base, and Optimism, by reducing transaction processing costs by 40-60%. Storage requirements decrease significantly, allowing validators to complete more datasets in less time and significantly improving Ethereum's transaction processing capacity. Additionally, this trimmed-down data processing method supports home stakers and validators without requiring them to upgrade to enterprise-grade infrastructure.

2. Increase in Block Gas Limit

The Fusaka Upgrade also increases Ethereum's block gas limit from 36 million to 60 million, allowing each block to hold more computation and data. This simply means more transactions can be processed on Ethereum's main network, improving network throughput. Complex smart contracts will also have more room to execute without hitting data limits.

3. Passkey Support

Fusaka Upgrade ushers in a major shift in passkey support by introducing the secp256r1 curve, which helps with device-specific passkeys and signing. Simply put, wallets can tap into hardware security modules and initiate web authentication directly from a device across multiple modern apps, enabling smoother onboarding, data recovery, and more.

This enhances user experience without the complexity or expense of verifying signatures on-chain.

4. EVM Improvements

EVM or Ethereum Virtual Machine is the computation engine for Ethereum and its layer-2 solutions. It is the central core of the entire functioning of the Ethereum blockchain and associated solutions. Fusaka paves the way for improvements to Ethereum's core engine, such as the EVM Object Format, New Opcodes, and more.

The EVM Object Format is an upgrade to the smart contract programming model that clearly separates code and data, enabling faster data validation and supporting data optimisation. EOF also helps developers improve command execution, reducing errors and increasing speed.

Opcodes are basic commands that EVM can execute, such as ADD, SUBTRACT, STORE and more. Fusaka adds more commands to the list, such as CLZ (Count Leading Zeros). This will greatly improve and speed up everyday tasks such as verifying digital signatures, processing crypto proofs and more.

5. Blob Base-Fee Linked to Execution Costs & MODEXP Gas Cost Increase

Ethereum's various layer-2 solutions, such as Base, Optimism, and others, experience varying transaction traffic and activity spikes, which in turn lead to varying node demand. To keep execution costs fair, the Fusaka Upgrade has introduced a feature that links the blob base-fee to execution costs. For the uninitiated, blobs are data containers which are data storage packets, a concept introduced in the Dencun upgrade of March 2024.

By linking the blob base-fee to execution costs, the Fusaka upgrade helps iron out any fee anomalies that could arise from varying transaction processing demand, which various layer-2 solutions of Ethereum may be routing to the main Ethereum blockchain.

Another development in the area of transaction cost is the MODEXP gas cost increase. The Fusuka upgrade raises the gas cost of a specific complex calculation, thereby preventing a single transaction from clogging the network. The modular exponential precompiles, or MODEXP, prevents monopolising the network's processing time, and its price rise reflects the actual computational resources needed to process this transaction.

Earlier, layer-2 solutions paid minimal fees to the Ethereum network. The Fusaka upgrade changes that, effectively enabling L2 fees to contribute to ETH burning and thereby curbing the token's supply, potentially leading to a price increase.

Currently, ETH issues around 620,000 tokens per year while burning 350,000. The fees incurred when moving from L2S to Ethereum are expected to contribute to another 200,000 to 400,000 tokens being burned per year, tightening the supply of ETH in the coming years.

6. Deterministic Proposer Lookahead

This feature of the Fusaka upgrade helps the Ethereum network predict who will propose data blocks in advance. The Beacon Chain can identify upcoming block proposers in advance, enabling overall network coordination, improving transaction processing speed, and supporting features such as preconfirmations.

7. Capping Execution Block Size Limit

Fusaka caps the maximum block size for execution payloads at 10MiB. This keeps validation times predictable and reduces any chances of network delays/ attacks from oversized blocks that could cause a cascading effect on network efficiency and speed.

Fusaka Upgrade Launch Date and Time

The Fusaka Upgrade launched on December 03, 2025, at a slow 13, 164, 544 at around 21:49 UTC. This translates to December 04, 2025, 3:19 am IST.

Fusaka Upgrade Benefits for Users

The Fusaka Upgrade benefits every stakeholder across the entire Ethereum ecosystem – developers, layer-2 networks, validators & node operators, DeFi users, ETH investors/traders, and more. Let's look at a detailed breakdown of how the Fusaka Upgrade impacts the following users/engagers of the Ethereum network:

DeFi Users

DeFi users participating in decentralised finance by lending and borrowing on DEXs stand to benefit greatly from the Fusaka upgrade in the following ways:

•  DeFi transactions will become faster and cheaper.
• Yield farming will become more affordable and economical. Yield farming is a way to learn passive income by lending or staking one's crypto holdings in a liquidity pool to offer liquidity on DeFi platforms.
• The increased gas limit will make more complex DeFi transactions easier to execute.
• A more sophisticated Ethereum network will, over time, usher in innovative DeFi products and services.

Developers

Developers building dApps on Ethereum are also poised to leverage the benefits of the Fusaka upgrade in the following ways:

• The improvements to the EVM (Ethereum Virtual Machine) make it easier to write, test, and optimize smart contracts. Code separation from data reduces bugs and improves overall security.

• CLZ opcode and secp56r1 support improves interaction with various crypto apps, especially mobile-friendly crypto wallets, helping developers achieve a superior user experience.

• The expansion of blobs or data sets allows developers to create more complex apps that would have otherwise faced roadblocks with the earlier data processing and management capabilities before the Fusaka Upgrade.

ETH Holders/Investors

Traders and investors in the ETH token enjoy the following benefits:

• Cheaper transactions across the Ethereum network in layer-2 solutions, NFTs and DeFi by at least 40% of the original transaction costs.

• Overall improvement in the Ethereum infrastructure, resulting in faster transaction processing, efficient data handling, and a smoother and more reliable ecosystem.

• The increased gas fees from layer-2 solutions to Ethereum will also lead to higher ETH burn, tightening the ETH supply in the long term and helping support the token's price, delivering more value to traders and token holders.

Layer-2 Networks

Both Optimistic rollups and ZK-Rollups on the Ethereum ecosystem, such as Optimism, Arbitrum, zkSync, Polygon, Base and more, are poised for several benefits from the Fusaka upgrade, including:

• Layer-2 networks benefit from higher transaction processing capacity on the main Ethereum network. Larger transactions that would earlier hit bottlenecks would now be processed seamlessly.

•  Layer-2 solutions also stand to enjoy reduced transaction processing costs.

• Overall, L2S can attract new users and increase trading volumes by offering efficiency, lower costs, and faster speeds.

Validators/Node Operators

• Validators benefit from simplified operations with the Fusaka upgrade, eliminating the need for high-end infrastructure. Validators can work with standard networks and hardware without investing in enterprise-grade infrastructure.

• Validators also enjoy greater predictability thanks to improvements in the network protocol and deterministic block proposer selection. This makes handling high traffic and complex transactions easier, eliminating bottlenecks and delays.

• Thanks to these factors, we can expect more validators to join the Ethereum network in the coming months.

For the crypto world at large, Ethereum's enhanced capabilities in data management, transaction cost and processing give a renewed thrust to smart contracts and DeFi. We stand to witness further influx of capital, higher trading volumes and unprecedented growth for the Ethereum network and the cryptocurrency space as a whole. Ethereum's aim to be the world's smart contracts computer is now within sight.

What is Next for Ethereum?

Ethereum's evolution began with The Merge in 2022, which transitioned the network from proof-of-work to proof-of-stake consensus, ushering in the network's efficiency era. Post this, the Shanghai upgrade (2023) and the Dencun (2024) upgrade shaped Ethereum's cost efficiency, data storage models, transaction processing and more.

The Pectra upgrade in 2025 set the groundwork for the Fusaka upgrade, both of which greatly improved validator flexibility and transaction processing speed.

In turn, the Fusaka upgrade serves as a precursor to the upcoming Glamsterdam upgrade. The next Ethereum upgrade, Glamsterdam, is expected to roll out in 2026. This upgrade takes PeerDAS a step further with Danksharding, Ethereum's long-term, rollup-centric scaling plan to increase transaction processing speed to 100k+ per second. Verkle Trees will also be introduced in this upgrade to make nodes lighter and even more efficient. Further improvements to historical data, functionality, and account abstraction are expected to take effect. By the end of 2026, Ethereum will have realised its vision of becoming a massive global settlements network that is:

·   Scalable – handling millions of transactions through thousands of validators

·   Secure – maintaining robust security powered by a sophisticated network

·   Decentralised – any user can become a validator without the need to invest in enterprise-grade infrastructure.

In the near term, the Fusaka upgrade will achieve the following for Ethereum:

·   A change in the overall monetary landscape of Ethereum with increased fees navigating from L2, reduced transaction costs and the ability to monetise scalability

·   Lowered fees and ease of scaling for layer-2 solutions

·   Superior data management for Ethereum and EVM

·   Higher demand for ETH, a possible supply crunch of the token, leading to a price escalation

·   Improved user experience, enhancing retail adoption of Ethereum and its L2S

·   Overall network stability and resilience

FAQs

1. How will Fusaka Upgrade impact Ethereum's price?

Analysts anticipate that the Fusaka upgrade could usher in a period of supply crunch for ETH, potentially pushing its price up after a fairly uneventful phase for the cryptocurrency.

Previously, layer-2 networks paid only negligible fees to the Ethereum network. With the Fusaka upgrade, that change as L2 fees will now help fuel ETH burns, reducing the token's supply and potentially supporting its price.

Aside from this, the Fusaka upgrade will positively impact Ethereum's price due to the operational efficiency, scalability and security it brings. The PeerDAS feature will usher in unprecedented data efficiency and high processing speeds, which should, in turn, attract more trading volumes to Ethereum and its L2S, thereby pushing the price of ETH up.

2. What is the Launch Date of Fusaka Upgrade?

The Fusaka Upgrade launched on December 03, 2025, at slots 13, 164, and 544, around 21:49 UTC. This translates to December 04, 2025, 3:19 am IST.

3. What is the Next Upgrade of Ethereum after the Fusaka Upgrade?

The next upgrade after the Fusaka Upgrade is Glamsterdam, scheduled for 2026. It will build on PeerDAS' features by introducing Danksharding, Ethereum's long-term scaling design that aims to boost transaction speeds to over 100,000 per second. The upgrade will also add Verkle Trees to make nodes smaller and more efficient, along with other improvements related to historical data, functionality, and account abstraction. As Ethereum realises the benefits of the Glamsterdam upgrade, the network will have achieved superior network capabilities, transaction processing speed, and scalability while upholding the tenets of decentralisation, paving the way for its vision of becoming the world's decentralised computer.