Author: Tanay Ved Source: coinmetrics Translation: Shan Ouba, Jinse Finance

Key Takeaways

• Fusaka significantly expands Ethereum's scalability by increasing blob capacity and deploying PeerDAS nodes, building a more efficient data availability system.

• The 60 million gas cap increase and execution layer optimizations significantly improve L1 throughput.

• Optimized fee mechanisms and user experience upgrades lay the foundation for a more unified and cost-effective L1-L2 ecosystem.

• The optimized fee mechanism and user experience upgrades lay the foundation for a more unified and cost-effective L1-L2 ecosystem.

Fusaka Upgrade Overview

Ethereum will undergo its next upgrade on December 3, 2025 at 9:49 PM UTC (slot 13,164,544). This hard fork is named "Fusaka". Following the naming convention of previous forks, the Fusaka upgrade integrates the execution layer "Osaka" upgrade and the consensus layer "Fulu" upgrade.

Following the Pectra upgrade in May, the Fusaka upgrade is an important step in Ethereum's scaling roadmap, which will improve network performance, increase block capacity, improve Rollup cost-effectiveness, and optimize user experience. The upgrade also introduces the "Block Parameter Only (BPO)" fork mechanism, which can safely increase block capacity as Rollup demand grows.

Earlier this year, the Ethereum Foundation announced its "Protocol" strategy, centered around three long-term goals: Layer 1 network scaling, block size expansion, and user experience optimization. The Fusaka upgrade is the first upgrade to fully align with this unified vision, marking a turning point in Ethereum's scaling and accessibility improvement plans. This article will break down the key changes of the Fusaka upgrade in detail, and the expected impact of its activation on the Ethereum mainnet, Layer 2 Rollups, transaction costs, and user experience. Block Size Expansion Last year's Dencun upgrade introduced "blobs," a cost-effective way for rollups to store transaction data on the Ethereum mainnet. Since then, blobs have been widely adopted thanks to rollup projects such as Base, Arbitrum, and Lighter. This has often led to near-saturation of blob usage (currently approaching the target of 6 blobs per block), increasing the risk of exponential growth in rollup fees. The demand for higher data availability (DA) makes blob space a key bottleneck for Ethereum scaling, and Fusaka is a solution proposed to address these limitations. PeerDAS: Peer Data Availability Sampling PeerDAS (EIP-7594), also known as Peer Data Availability Sampling, is arguably one of the most important upgrades in the Fusaka release, directly aligning with the goals of expanding L1 consensus and blob data. PeerDAS provides Ethereum nodes with a more efficient way to check the availability of blob data. Nodes do not need to download the entire blob content; instead, they verify data availability by sampling a small amount of data, thus providing the same security guarantees without increasing the burden on L1 consensus nodes. Expected Impact: Nodes only store approximately 1/8 of each data block, achieving higher block throughput without increasing hardware requirements. This enables Ethereum to securely increase blob throughput, a core driver of rollup capacity. Lower data availability costs reduce L2 transaction costs and improve the reliability of batch posting. This lays the foundation for full sharding and higher overall transaction throughput across the entire ecosystem. For example, Base stated in a blog post that the Fusaka L2 scalability improvements will allow it to "double chain throughput within 2 months."

Fork containing only Blob parameters (BPO)

Ethereum can now safely increase blob capacity because PeerDAS reduces the bandwidth and storage space required for nodes to verify blob data. Fusaka introduced a fork containing only blob parameters (BPO) designed to increase the number of blobs per block over time. This allows Ethereum to adjust blob parameters without waiting for a full hard fork, providing the protocol with a more flexible and responsive scaling tool.

Upcoming BPO branch:

Expected Impact:

• Increased DA Bandwidth:Increases rollup capacity from 6 blobs per block to 128 blobs, and reduced L2 transaction fees. Flexible scalability: The blob parameter can be dynamically adjusted based on demand growth. A gradual development path: Consistent with Ethereum's roadmap to reduce Rollup execution costs and achieve scalable data availability. Blob base fee adjustment: As Blob capacity increases, Ethereum's Blob fee market will play a greater role in coordinating Rollup demand. Currently, Rollups can obtain blobs at almost no cost. Because demand is relatively insensitive to price, and prices do not always smoothly adapt to changes in usage, Blob fees typically remain at a minimum of 1 wei. This results in a fee mechanism in a "price inelastic" range, limiting its responsiveness to changes in usage.

  

  Source: Ethereum EIP 7198

  Fusaka introduced a lower bound on the blob base fee by pegging the blob base fee to a portion of the L1 base fee.

  This prevents blob prices from plummeting to zero and ensures that the fee adjustment mechanism continues to function effectively as blobspaces scale. More stable bulk pricing: Prevents the fee market from falling into a minimum price trap. Predictable aggregation economics: Ensures that aggregation pays a reasonable baseline fee for data availability, without sudden or unstable fee increases. Minimal impact on user costs: Even with the new lower bound, L2 data costs remain only a fraction of a cent, with a negligible impact on user experience. Sustainable long-term economic benefits: The increased blob throughput due to compensation node processing means that blob fees currently contribute little to ETH burning, but may contribute more in the future as capacity expands. L1 Scaling: Fusaka also places great emphasis on L1 scaling. He improved Ethereum's Layer-1 execution capabilities through EIP-7935, raising the protocol's default gas limit to 60M. This directly increases the number of transactions that can be accommodated per block, resulting in higher throughput, less congestion, and lower gas fees.

  

  Data Source: Coin Metrics Network Data Pro

  Expected Impact:

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    Data source: Coin Metrics Network Data Pro

    In addition to increasing the gas limit, Fusaka has also introduced several improvements to enhance L1 execution efficiency and prepare for future network expansion.

    The new single-transaction gas usage cap prevents any single transaction from dominating a block and lays the foundation for parallel execution. Updates to the ModExp pre-compilation recalibrate gas costs and set clearer boundaries for operations, maintaining predictability in resource usage while throughput increases. Furthermore, the network layer has been simplified by removing outdated pre-merge fields, enabling faster and more efficient synchronization of Ethereum nodes. Fusaka also introduces updates designed to improve usability for users and developers. EIP-7951 adds native support for the secp256r1 elliptic curve, the signature standard used by Apple Secure Enclave, Android Keystore, and most consumer hardware. This allows wallets and applications to directly integrate familiar authentication processes (Face ID, Touch ID, WebAuthn) on Ethereum, lowering the barrier to user registration and enhancing security for retail and institutional users. These upgrades will help modernize Ethereum developers and user interfaces, making it easier to build secure, mainstream applications. In summary, the most direct impact of the Fusaka upgrade activation will be reduced Rollup fees, increased block throughput, and a significant expansion of Layer 1 network execution capacity. In the long term, larger block space, lower costs, and a steady improvement in Layer 1 network performance will collectively shape the economic model of Layer 2 settlement, influence ETH burning dynamics, and make the entire Ethereum ecosystem more coordinated and unified. While the long-term value impact ultimately depends on demand and adoption, the Fusaka upgrade lays a clearer and more scalable foundation for Ethereum's next phase of growth—one where Layer 1 and Layer 2 networks will work more seamlessly together, and the network will be better able to support more users, assets, and on-chain activity.