Author: Tanay Ved; Translator: Plain Language Blockchain
Key Points
Fusaka extends Ethereum's scalability through higher Blob capacity and a more robust PeerDAS efficient data availability system.
L1 throughput increases significantly with a higher 60M Gas cap and execution layer optimizations.
Improved fee mechanisms and user experience (UX) upgrades lay the foundation for a more unified and cost-effective L1-L2 ecosystem.
The improved fee mechanism and user experience (UX) upgrades lay the foundation for a more unified and cost-effective L1-L2 ecosystem.
Fusaka Overview
Ethereum plans to undergo its next upgrade on December 3, 2025 at 21:49 UTC (slot 13,164,544), codenamed the "Fusaka" hard fork. Fusaka combines the execution layer upgrade Osaka and the southern layer upgrade Fulu, following the architecture of previous forks.
Following Pectra in May, Fusaka represents a significant step forward in Ethereum's scaling roadmap, enhancing Layer-1 performance, increasing Blob capacity, improving the cost-effectiveness of Rollups, and delivering UX upgrades.
It also introduced the **Blob Parameter Dedicated (BPO) fork**, a method for securely increasing blobs as Rollup demand grows. Earlier this year, the Ethereum Foundation outlined its **protocol** strategy, which revolves around three long-term goals: **expanding L1, expanding blobs, and improving UX**. Fusaka is the first upgrade to fully align with this unified vision, marking a turning point in how Ethereum plans to scale and improve accessibility in the future. Expanding Blobs Last year's Decun upgrade introduced efficient **"blobs"**, an economical way to use Rollups to store transaction data on the Ethereum mainnet. Since then, blobs have been widely used, driven by Rollups such as Base, Arbitrum, and Lighter. This has led to near-peak blob usage (currently close to the target of 6 blob blocks), **posing a risk of exponential growth in Rollups**. The need for higher data availability (DA) has made Blob space a key bottleneck in Ethereum's scaling path, and Fusaka directly addresses these limitations. PeerDAS: Peer Data Availability Sampling PeerDAS (EIP-7594), or peer data availability sampling, is arguably the most important upgrade in Fusaka, directly aligning with the goals of scaling L1 and Blobs. PeerDAS introduces a more efficient way for Ethereum nodes to check the availability of Blob data. Instead of consuming a full node to download a Blob, data availability is verified by collecting small fragments of the data content, providing the same security guarantees without increasing the load on L1 relay nodes. Expected Impact: Nodes store only about 1/8 of each Blob, enabling greater Blob throughput without increasing hardware requirements. This allows Ethereum to safely increase Blob capacity, a core driver of Rollup capacity. Internal data availability costs lead to cheaper L2 transactions and more reliable batch releases. **This lays the foundation for full Danksharding and higher overall transaction freight across the entire ecosystem.** For example, Base stated in a blog post that the L2 scalability improvements after Fusaka will be able to "double its chain freight within 2 months." **Blob Parameter Dedicated (BPO) Fork** With PeerDAS reducing the bandwidth and storage required for nodes to verify Blob data, Ethereum can now safely increase Blob capacity. Fusaka introduced the **Blob Parameter Dedicated (BPO) fork**, which aims to **gradually increase the number of Blobs per block** over time. This allows Ethereum to **adjust Blob parameters while waiting for the full hard fork**, providing the protocol with a more flexible and responsive scaling tool. Upcoming BPO Fork: Early 2026: Increase from 6 to 12 slots (14,000,000 slots) Late 2026: Increase from 12 to 25 slots (15,500,000 slots) Early 2027: Increase from 25 to 50 slots (16,300,000 slots) src="https://www.hellobtc.com/d/file/202512/40fe5e243c4fab32b9eaf1394e18e3a1.jpg">Expected Impact:
More DA Bandwidth:Increases Rollup capacity from 6 Blobs per block to 128 Blobs, and reduces L2 transaction fees.
Flexible Scaling:Blob parameters can be dynamically adjusted as demand increases.
Incremental Development Path:In line with Ethereum's roadmap for achieving cheaper Rollup execution and scalable data availability.
Blob Base Fee Adjustment
As Blob capacity expands, Ethereum's Blob fee market will play a greater role in aligning with Rollup demand. Currently, Rollup consumption on Blobs is almost zero. Because Blob prices typically remain at a minimum of 1 wei, demand is relatively insensitive to price and does not always adjust smoothly with changes in usage. This results in the fee mechanism remaining in an "inelastic" range, limiting its responsiveness to changes in usage. Fusaka introduces a lower bound on the Blob base fee by linking the Blob base fee to a portion of the L1 base fee. This prevents the Blob price from falling to zero and maintains compatibility with the fee adjustment mechanism as the Blob space expands. More stable Blob pricing: Preventing the fee market from falling to the lowest price. **Predictable Economics of Rollups:** Rollups ensure that they pay a reasonable baseline fee for data availability, without sudden or erratic fee jumps. **Minimal Impact on User Costs:** Even with a new lower bound, L2 data costs remain as low as a few cents, with negligible impact on user experience. **Sustainable Long-Term Economics:** Increased node processing of Blob throughput contributes adaptively to ETH fees today, and likely will continue to do so over time and with capacity expansion. **Scaling L1:** Fusaka also places great emphasis on L1 scaling. It improves Ethereum's Layer-1 execution capabilities through **EIP-7935**, increasing the protocol's default gas cap to **60M**. This directly increases the number of transactions that can be accommodated in a block, resulting in **higher throughput, less congestion, and cheaper gas fees**. Expected Impact: **Higher Throughput:** More computation per block increases the total L1 capacity. Supports more complex applications: A larger gas cap supports complex contract execution. Less front-end congestion under load: The extra capacity reduces front-end congestion during peak demand periods. Helps maintain low costs: The additional capacity supports the current low-cost environment (<0.4 gwei). In addition to the increased Gas cap, Fusaka introduces improvements that make L1 execution **clearer** and prepare for future network expansion. The new per-transaction Gas usage cap prevents any single transaction from dominating a block and strengthens the foundation for **timber execution**. Updates to **ModExp pre-compilation** recalibrate Gas costs and set clearer boundaries for operations, **maintaining predictability of resource usage as cargo grows**. The network layer has also been simplified by removing outdated pre-merge fields, making Ethereum node synchronization faster and easier. Fusaka also introduced updates to improve usability for users and developers. EIP-7951 adds native support for the secp256r1 elliptic, the signature standard used by Apple Secure Enclave, Android Keystore, and most consumer hardware. This allows wallets and applications to integrate similar authentication processes (Face ID, Touch ID, WebAuthn) directly onto Ethereum, thereby reducing onboarding and enhancing security for retail and institutional users. These improvements help upgrade and modernize Ethereum's developer and user interface, making it easier to build secure, mainstream-oriented applications. Conclusion: With the activation of Fusaka, the most direct impacts will be reflected in the reduced upfront Rollup costs, higher Blob throughput, and a significant expansion of L1 execution capabilities. Simultaneously, the combination of larger Blob space, reduced overhead, and continued improvements in L1 performance will shape the finances of L2 settlement, influence related dynamics, and clean up the system's broader Ethereum ecosystem timeline, giving it a sense of internal aggregation. While the long-term value impact ultimately depends on demand and adoption, Fusaka lays a clearer and more scalable foundation for Ethereum's next phase, in which L1 and L2 functionalities will work together more seamlessly, and the network will be better positioned to support a higher capacity of users, assets, and on-chain activity.
