Ethereum has long been the backbone of decentralised applications, powering everything from DeFi protocols and NFTs to complex dApps and decentralised governance systems. Since its launch in 2015, Ethereum has continually evolved to meet the growing demands of the blockchain ecosystem. Over the years, several major network upgrades have helped Ethereum scale, improve efficiency, and maintain security.
Some notable upgrades include The Merge (2022), which transitioned Ethereum from energy-intensive proof-of-work (PoW) to the more sustainable proof-of-stake (PoS) system; Dencun (2024), which introduced “blobs” to improve Layer-2 data handling; and Pectra (2025), which further expanded blob capacity and refined validator functionality. Each of these upgrades played a crucial role in preparing Ethereum for mass adoption.
Now, Ethereum has launched its latest major upgrade, the Fusaka hard fork. Fusaka represents a significant step forward, enhancing Ethereum’s data handling capabilities, increasing block capacity, and laying the groundwork for the network’s long-term scalability and efficiency. But what is Fusaka? Why does Ethereum need a Fusaka upgrade? Why is it important for developers, users, and the Ethereum ecosystem as a whole?
Why Ethereum Needed Fusaka
Ethereum’s growth over the past decade has been remarkable. Millions of users interact with the network daily, executing transactions for decentralised finance (DeFi), NFTs, games, and Layer-2 rollups. While Ethereum has introduced several upgrades over the years, the network still faces inherent challenges that risk slowing its adoption if not addressed:
1. Scalability Pressure:
Ethereum’s original architecture was not built to handle millions of transactions per day. Even after The Merge and previous upgrades like Dencun, the base layer can become congested during high-demand periods, leading to higher fees and slower transaction times.
2. Layer-2 Data Bottlenecks:
Layer-2 rollups, designed to improve scalability, rely on publishing large amounts of data to Ethereum’s base layer. Storing and verifying this data had become increasingly resource-intensive, putting strain on nodes and limiting how much Layer-2 applications could scale.
3. Node Resource Constraints:
As data volumes grow, running a full Ethereum node has become more expensive and resource-heavy. This can discourage smaller validators or community participants from operating nodes, risking network centralisation.
4. Future-Proofing:
Ethereum is not just a network for today; it is aiming to host billions of users and thousands of high-throughput applications in the near future. To support this, the network must be flexible, efficient, and prepared for rapid Layer-2 adoption and more data-intensive applications.
The Fusaka upgrade directly addresses these challenges, ensuring Ethereum remains scalable, accessible, and sustainable while maintaining decentralisation and security.
What Is Fusaka?
Fusaka is a comprehensive hard fork that combines improvements across both Ethereum’s consensus and execution layers. Its name is a blend of “Fulu” (the consensus-layer component) and “Osaka” (the execution-layer component), following Ethereum’s tradition of giving upgrades meaningful, memorable names.
Fusaka is designed to expand Ethereum’s scalability and efficiency, particularly for Layer-2 rollups and high-traffic decentralised applications. Unlike incremental updates, Fusaka introduces multiple Ethereum Improvement Proposals (EIPs) that target data availability, block throughput, and node efficiency, creating a foundation for Ethereum to support more users, more transactions, and more complex applications without compromising decentralisation or security.
Features of the Fusaka Upgrade
Fusaka addresses three major areas: data availability, block capacity and throughput, and usability and future-proofing. Each of these aspects brings tangible improvements for the network and its participants.
1. Data Availability & Node Efficiency: PeerDAS
One of Fusaka’s headline features is Peer Data Availability Sampling (PeerDAS), introduced through EIP-7594. In simple terms, this allows Ethereum nodes to verify Layer-2 rollup data by sampling small, random pieces of the data blobs, rather than downloading the entire dataset.
Previously, every validator needed to store full blob data to ensure its availability. As Layer-2 rollups became more popular and data volumes grew, this requirement created significant storage and bandwidth bottlenecks, limiting scalability. PeerDAS removes that barrier by enabling nodes to verify data integrity with a fraction of the resources.
The benefits are clear: smaller operators and community validators can participate without investing in high-end hardware, which strengthens decentralisation. At the same time, Layer-2 rollups can publish larger and more frequent data blobs, paving the way for higher throughput and faster transactions. This shift is foundational for Ethereum’s roadmap toward massive adoption.
2. Block Capacity & Throughput
Fusaka introduced increased block capacity, raising the block gas limit to approximately 60 million gas per block, up from the previous 36-45 million. To prevent a single transaction from monopolising block space, a per-transaction gas cap of roughly 16.7 million gas has been implemented.
These changes have significant implications. By increasing block capacity, Ethereum can now handle more transactions per block, reducing congestion and improving performance during peak usage times, such as popular NFT launches or DeFi events.
For developers and builders, this means Layer-2 rollups and dApps can operate more efficiently. Large-scale projects that rely on bundling many transactions into single blocks will experience lower latency, more predictable gas fees, and smoother performance, which directly benefits users interacting with Ethereum-based applications.
3. Usability, Node Efficiency & Future-Proofing
Beyond throughput and data verification, Fusaka also includes upgrades designed to improve node efficiency and long-term sustainability. These changes include support for modern cryptographic standards (like EIP-7951, introducing secp256r1 elliptic curve support), as well as history pruning and simplified receipt structures (EIP-7642).
By making nodes lighter and reducing the storage and computational demands, Fusaka ensures that running an Ethereum node remains accessible to a wide range of operators. This is crucial for maintaining network decentralisation, even as Ethereum continues to grow.
Furthermore, Fusaka introduces the concept of Blob-Parameter-Only (BPO) forks, allowing Ethereum to adjust blob capacity flexibly between major upgrades. This means the network can scale data availability and throughput more smoothly in the future without requiring full hard forks, ensuring that Ethereum remains agile in response to growing usage.
Why Fusaka Matters
Fusaka is more than just a technical update, it’s a strategic advancement for Ethereum.
- For users, it promises lower fees, faster transactions, and smoother Layer-2 interactions. Popular applications and DeFi platforms will feel less congested, making everyday usage more seamless.
- For developers, Fusaka provides a robust foundation to build scalable applications, enabling more complex, data-heavy dApps and Layer-2 solutions to thrive.
- For validators, the upgrade reduces hardware requirements and operational costs while maintaining security and decentralisation.
For the Ethereum ecosystem, Fusaka strengthens the network’s position as the leading smart-contract and settlement layer, capable of supporting mass adoption without sacrificing performance or security.
While Fusaka makes significant improvements, it is not a cure-all. The upgrade does not fully enable parallel execution or unlimited scalability. Validators must update their software to remain in sync, and the benefits will scale gradually as developers leverage the new block capacity and data-handling features.
Nonetheless, Fusaka is a critical milestone in Ethereum’s ongoing journey toward becoming a globally scalable and accessible blockchain platform.
Conclusion
Ethereum’s Fusaka upgrade represents a major step toward a more efficient, scalable, and user-friendly blockchain. By improving data availability through PeerDAS, expanding block capacity, and future-proofing node operations, Fusaka positions Ethereum to handle a growing ecosystem of Layer-2 rollups, dApps, and users.
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