Ethereum developers introduced a major evolution on December 3, 2025, when they activated the Fusaka Upgrade, which combines improvements across both the execution and consensus layers. The community calls the upgrade “Fusaka” because it merges two coordinated updates: Osaka on the execution layer and Fulu on the consensus layer. Together, these updates introduce PeerDAS, a new data-availability sampling system that fundamentally changes how Ethereum handles L2 data.
The network continues its shift toward modular architecture, and Fusaka strengthens that direction. Instead of focusing on one-off features, the Ethereum roadmap now prioritizes scalable infrastructure, lower fees, and decentralization. Fusaka accelerates this evolution by shrinking node requirements, increasing blob capacity, and creating a foundation for future rollup expansion.
PeerDAS — The Heart of the Fusaka Upgrade
Ethereum historically required each node to download and store all blob data that L2 rollups submitted. This approach protected the network, but it also created a heavy burden on node operators. As L2 activity grew, blob data volumes surged, and node operators needed larger storage, higher bandwidth, and more computing power. That situation threatened decentralization, because only well-funded entities could run full nodes comfortably.
Developers solved this challenge through PeerDAS (Peer Data Availability Sampling). PeerDAS introduces a new method of verifying data availability. Instead of storing all blob data, each node now samples small chunks from the entire dataset. The node uses probabilistic checks and cryptographic proofs to confirm that all data remains available across the network. A node no longer downloads full blobs; it only downloads a fraction.
This design reduces a node’s data load dramatically. Developers estimate that each node stores only around one-eighth of the previous blob requirements. Because the network now distributes the data load more efficiently, operators can run nodes with far fewer resources. This reduction strengthens decentralization because small operators can rejoin the network with modest hardware.
PeerDAS also increases blob capacity. Before Fusaka, Ethereum handled a limited number of blobs per block, which constrained L2 throughput. The upgrade expands this limit significantly, and the network now supports up to eight times more blob data. L2 rollups can publish more data and process more transactions without hitting bottlenecks. Together, sampling and higher capacity create a powerful foundation for long-term scaling.
Fusaka Improves Layer-2 Performance and Lowers Fees
Layer-2 rollups depend on Ethereum for data availability. Rollups publish batches of transactions as blobs, and users pay the costs associated with that data. Higher blob capacity and lower data load lift enormous pressure from the network. Rollup developers can post more data for less cost, and users directly benefit from lower fees.
The Fusaka upgrade lowers L2 fees in multiple ways:
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It increases available blob space, so rollups no longer compete aggressively for limited capacity.
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It shrinks blob data requirements, so validators can process more data with fewer resources.
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It raises throughput across the entire ecosystem, so congestion drops even during busy periods.
Users often encounter expensive fees during NFT mints, memecoin cycles, or spikes in DeFi activity. Fusaka reduces those spikes. Traders can settle transactions faster, NFT developers can run large drops at lower cost, and gaming projects can onboard far more users without fear of chain overload.
Rollup developers also gain freedom to build more ambitious designs. High-frequency trading platforms, real-time gaming engines, social-graph networks, and complex DeFi systems can now rely on more spacious and affordable blob data. Fusaka enables these apps to scale without hitting structural constraints.
The Upgrade Strengthens Decentralization
Ethereum draws strength from its decentralized validator set. A large, globally distributed network of independent node operators protects the chain from censorship and centralization. However, before Fusaka, rising storage and bandwidth demands discouraged small operators from participating.
The PeerDAS model reverses this trend. Nodes now process less data, store fewer blobs, and operate with lower costs. An operator can run an Ethereum node with less hardware, which invites more individuals to join. Decentralization increases when thousands of people can run nodes without high expenses.
Fusaka also encourages healthy diversity across clients. When node operation becomes easier, developers feel more motivated to maintain independent clients, improve codebases, and optimize performance. Client diversity strengthens the network’s security because multiple implementations guard the chain from bugs in any single client.
Fusaka Improves Ethereum’s Institutional Appeal
The upgrade introduces technical changes that attract institutional users. One of the most important additions involves improved support for modern authentication systems, including passkey-based cryptography. Many enterprises prefer hardware-secured authentication because it aligns with their security policies. Fusaka enables validators, institutions, and developers to integrate these secure authentication flows with Ethereum.
Enterprises also care about predictable costs, fast settlement, and high reliability. Fusaka improves all three. Rollups now post larger batches at lower costs, and the network handles more data without slowing down. Institutions that plan to build high-volume applications, tokenization platforms, or settlement layers can now rely on Ethereum with more confidence.
Fusaka Deepens Ethereum’s Long-Term Roadmap
Ethereum’s roadmap includes multiple phases: the Surge, Verge, Purge, and Splurge. Each phase addresses structural layers of scalability, storage, lightweight client verification, and long-term optimizations.
Fusaka directly supports these phases because:
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It strengthens data availability for the Surge.
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It simplifies node operation, which helps the Purge.
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It makes future sharding phases easier to implement.
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It prepares the network for higher-throughput rollups.
The upgrade signals a period of maturation. Ethereum now focuses on infrastructure that can support millions of daily users and thousands of large applications. Developers no longer chase flashy features; they focus on deeper systems that sustain long-term growth.
Stakeholders Feel the Impact Across the Ecosystem
Developers
Developers gain the largest advantage. They can create more ambitious applications with high data requirements. They can design more complex rollups, integrate advanced zero-knowledge systems, or deploy gaming engines that generate continuous data flows. With cheaper blob costs and more capacity, developers can innovate with fewer constraints.
Users
Everyday users experience lower fees, faster confirmations, and smoother interactions across dApps. NFT collectors can mint without huge spikes. Traders can execute L2 swaps with minimal friction. Gamers can enjoy responsive in-game actions on blockchain-backed systems.
Validators and Node Operators
Validators face lighter workloads. They no longer struggle with heavy blob storage. Bandwidth costs drop. Operators can run nodes on more affordable hardware. This shift renews enthusiasm among independent operators and reduces reliance on large infrastructure providers.
Institutions
Institutions appreciate stability. Fusaka delivers predictable performance, modern authentication, and a more reliable L2 environment. Large financial institutions, enterprise developers, and global corporations feel more comfortable integrating Ethereum into their systems.
Conclusion: Fusaka Marks a Powerful Turning Point for Ethereum
Ethereum enters a new era with the Fusaka upgrade. The network strengthens its foundation, improves scalability, lowers L2 costs, and expands blob capacity. PeerDAS reshapes how Ethereum manages data and transforms node operation, developer experience, and decentralization.
The upgrade gives Ethereum the ability to scale responsibly, attract institutional attention, and support mass adoption. Fusaka does not end Ethereum’s evolution; it accelerates it. The network now carries the infrastructure, efficiency, and global readiness to support the next decade of Web3 innovation.
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