Key Highlights
The Fusaka upgrade boosts Layer-2 data throughput by up to 8x for cheaper rollup transactions.
The block gas limit increases from 45 million to 60 million, expanding the network’s processing capacity.
The upgrade enables faster, “instant-feel” user experiences and introduces support for secure passkey (WebAuthn) logins.
The Ethereum core development community has announced that the Fusaka network upgrade is scheduled for mainnet activation on December 3.
The developers view this hard fork as essential to the network’s long-term viability and scalability. It aims to incorporate several significant improvements into the blockchain’s consensus and execution layers.
1/ Fusaka is coming December 3rd.Ethereum’s next major upgrade shows that the network can grow to meet global demand, without compromising on decentralization or permissionlessness.Whether you’re a user, builder, institution, or operator, here’s how Fusaka will impact you. pic.twitter.com/FKsqdZiwMM— Ethereum (@ethereum) November 28, 2025
The update ensures that the network can accommodate rising demand worldwide without compromising permissionlessness or decentralization. Setting sights on full scalability, the upgrade is pivotal in realizing a fully scalable Ethereum.
Core features and mechanics
Fusaka is a multifaceted upgrade that targets data handling, transaction speed, and node sustainability. Its main feature is Peer Data Availability Sampling, proposed under EIP-7594, which will fundamentally change how Layer-2 (L2) data is validated. This will unlock up to 8x data throughput by allowing validators to validate data through sampling of its availability without needing to download the entire dataset.
For rollups, this means lower blob fees and more space to grow (plus lower fees for users). To accommodate higher traffic, the upgrade increases the block gas limit, moving it from approximately 45 million to 60 million. This change expands throughput, while history expiry enables lighter, cheaper nodes long-term, thereby ensuring Fusaka’s upgrades grow capacity while keeping node ops sustainable.
Additionally, the update brings some important changes that enhance the user experience. Fusaka brings Ethereum closer to the ease of consumer apps: faster, safer, and easier to use. Data scaling means near-instant transactions. The new architecture also enables mobile-ready wallets to more cheaply support passkeys for secure logins using your phone’s hardware.
Origin and background
The name Fusaka combines two internal development code names: Fulu, which referred to the consensus layer upgrade (following the star naming theme), and Osaka, which referred to the execution layer upgrade (named after a Devcon host city). The successful combination of these two major protocol improvements into one hard fork is proof of dependable progress: two major upgrades in one year, evolving in public, with no network downtime.
This upgrade continues the network’s steady sequence of enhancements, building on the foundation set by the 2022 Merge to Proof-of-Stake and the subsequent Dencun upgrade, which first introduced the mechanism for data “blobs.” Fusaka directly addresses the need to increase the network’s capacity to handle the growing volume of data posted by L2 scaling solutions.
The impact of the Fusaka upgrade is expected to be felt most acutely by users and application builders. The developers noted that Fusaka lays the groundwork for ‘instant-feel’ user experiences.
This is facilitated by preconfirmations that allow for reduced transaction latency—moving from minutes to milliseconds. Combined with lower transaction costs, this opens the door for a new tier of applications, particularly in high-frequency sectors like gaming and decentralized finance (DeFi).
For institutional and enterprise users, the upgrade includes changes that will make it easier to integrate blockchain infrastructure into existing corporate security standards. Native support for the secp256r1 curve aligns Ethereum cryptography with existing standards, while blob base-fee tuning makes fees more predictable.
Meeting global demand
In all, the upgrade demonstrates that the network can scale up to meet global demand without sacrificing either decentralization or permissionlessness.
The Fusaka hard fork, scheduled on December 3, introduces a vast set of changes targeted at data layer scaling and efficiency improvements in execution. By integrating core features such as PeerDAS and increasing the gas limit, the network continues to position itself as a base layer for modular scaling. Most of the changes take place at the protocol level; however, their intended impact is to create a faster, cheaper, and safer experience for all users and builders in this ecosystem.
Also Read: Ethereum Foundation to Co-Host First App Town Hall at Devconnect