Vitalik Buterin Unveils Fusaka: Ethereum’s Boldest Scaling Upgrade

Ethereum’s Fusaka upgrade, launching December 3, introduces groundbreaking PeerDAS technology to tackle scalability, economic sustainability, and network congestion.

Ethereum is preparing for its most significant transformation yet. Co-founder Vitalik Buterin has announced Fusaka, a sweeping upgrade designed to redefine how the blockchain manages data, scalability, and economic sustainability. Scheduled to go live on December 3, 2025, Fusaka introduces PeerDAS, a system that could revolutionize blockchain architecture by eliminating the need for any single computer to download the full Ethereum ledger.

Fusaka will fix this.

But also, safety first is of the utmost importance for Fusaka. The core feature, PeerDAS, is trying to do something pretty unprecedented: have a live blockchain that does not require any single node to download the full data.

The way PeerDAS works is that… https://t.co/go6QsqjaFC
— vitalik.eth (@VitalikButerin) September 24, 2025

A Leap Forward in Blockchain Scalability

At the heart of Fusaka lies PeerDAS (Peer-to-Peer Data Availability Sampling). This system enables validator nodes to check only small, randomly selected pieces of data—rather than entire blocks—while still ensuring full data availability across the network.

Under current blockchain structures, every participant must store entire blocks, a model that creates bottlenecks as networks scale. PeerDAS changes that by:

Splitting data into small “chunks”, distributed across thousands of participants.
Allowing probabilistic verification that enough data exists to reconstruct a complete block.
Employing erasure coding, enabling missing pieces to be rebuilt if at least half of the data chunks remain accessible.

Buterin called the technology “unprecedented” for live blockchains, highlighting its potential to unlock massive scalability without compromising security.

Tackling Ethereum’s Network Congestion

Ethereum has been facing growing pressure at the base layer, even as Layer 2 networks like Arbitrum and Optimism expand. While these scaling solutions reduce costs, they also fragment the user experience and divert transaction fees away from Ethereum’s mainnet.

The congestion problem is clear in the validator queue system. At present:

Over 2 million ETH remain locked in exit queues.
Validators face 43-day delays to exit, compared to just seven days to enter.

Buterin defended the design, saying validator commitments require friction to protect security. He compared the obligation to “military service,” where quitting must not be effortless.

Fusaka aims to ease pressure by more than doubling blob capacity—a critical metric for scaling data throughput. Within two weeks of launch, blob capacity will expand from 6/9 blobs to 14/21, using automated parameter-only forks. This phased rollout begins conservatively and gradually ramps up as stability is confirmed.

Addressing Ethereum’s Economic Strains

Beyond technical scalability, Fusaka arrives at a critical economic moment for Ethereum. Revenue dropped 44% to $14.1 million in August 2025, one of the weakest months since early 2021, even as ETH reached a record high above $4,950.

The decline is tied to Layer 2 adoption, which lowers fees on the mainnet but also reduces Ethereum’s direct revenue. This has sparked concerns about the long-term sustainability of Ethereum’s economic model.

Buterin has suggested a potential remedy in low-risk DeFi protocols. He proposed that lending platforms offering modest yields on blue-chip stablecoins could act as Ethereum’s “Google Search”—a steady economic engine supporting broader network innovation. Platforms such as Aave, where users earn around 5% on stablecoins like USDT and USDC, were highlighted as examples of sustainable revenue without speculative risks.

Fusaka’s improvements are expected to lower transaction costs for such protocols, making them more accessible to everyday users who previously faced prohibitive gas fees.

A Phased and Cautious Rollout

Ethereum’s core developers are taking a conservative approach despite years of research into Fusaka. The upgrade includes 11–12 Ethereum Improvement Proposals (EIPs), targeting both scalability and node efficiency.

Notably, parameter-only forks will automatically adjust blob counts on a predetermined schedule. This eliminates the need for repeated full-scale network upgrades, reducing governance overhead and minimizing risk.

While PeerDAS significantly decentralizes block verification, certain centralized roles remain in the short term. Complete data blocks will still be required for broadcasting and emergency reconstruction when publishers fail to provide full data. However, these responsibilities demand only one honest participant among potentially many dishonest ones—a structure designed to minimize trust assumptions.

Future developments, such as cell-level messaging and distributed block building, aim to eliminate these transitional centralization points altogether. Different participants could then handle different aspects of block creation, further strengthening Ethereum’s decentralization.

Building on the Pectra Upgrade

Fusaka follows the successful Pectra upgrade in May 2025, which introduced account abstraction and raised validator staking limits from 32 ETH to 2,048 ETH. That upgrade also advanced infrastructure for social recovery wallets and more flexible smart contract execution.

With Fusaka, Ethereum continues to evolve into a more robust and scalable ecosystem capable of handling the next wave of global adoption. Improved data availability and throughput are expected to support both consumer-facing applications and institutional integrations, while keeping Ethereum’s hallmark security guarantees intact.

Ethereum at a Decade of Innovation

This latest milestone comes just weeks after Ethereum’s 10-year anniversary on July 30, 2025. From its early days as a smart contract platform to becoming a global financial infrastructure backbone, Ethereum has continually pushed technological boundaries.

Fusaka represents a decisive step in that journey—one that could determine whether Ethereum maintains its position as the leading decentralized platform amid intensifying competition. By addressing scalability, congestion, and economic sustainability in one coordinated upgrade, Ethereum is betting on an architecture designed not just for the next year, but for the next decade.

As Buterin and core developers prepare for the December launch, the crypto industry will be watching closely. If successful, Fusaka could become the defining breakthrough that secures Ethereum’s role in Web3’s future.