Interpreting Ethereum Fusaka Upgrade: The Evolution of Scaling Behind 12 EIPs

The Ethereum Fusaka upgrade, covering 12 EIPs, has entered the "substantial implementation" stage, marking a key step in Ethereum's transition to mainstream commercial applications and scalability improvements.
Expected to launch by late 2025, Fusaka aims to significantly reduce L2 transaction fees and enhance Ethereum's competitive edge through innovations like PeerDAS (EIP-7594) for data availability sampling and Verkle trees for node lightweighting.
Key upgrades include expanding Blob capacity (from 6 to potentially 72/block), optimizing EVM performance (EIP-7939, EIP-7951), and improving contract flexibility (EIP-7907), all while ensuring network stability with block size limits (EIP-7934) and dynamic fee adjustments (EIP-7892/7918).
Fusaka builds on previous milestones like The Merge (2022), Dencun (2024), and Pectra (2024), advancing Ethereum's roadmap toward scalability, decentralization, and mainstream adoption.
If successful, Fusaka could enable L2s to handle tens of thousands of TPS, benefiting DApps, DeFi, and gaming, while making on-chain interactions cheaper and faster for end users and enterprises.
Challenges remain, as Fusaka is still in testing, with its final timeline subject to change. However, it represents a potential watershed moment for Ethereum's expansion and usability.

Author: imToken

On June 20, at the 214th Ethereum Executive Core Developers Meeting (ACDE), core developers agreed to keep the final scope of the Fusaka upgrade basically unchanged, adding only one additional EIP (EIP 7939), covering 12 EIPs. This also marks that Fusaka has officially entered the "substantial implementation" stage from the "planning" stage.

As the largest hard fork bundle upgrade since The Merge, the market generally expects that if Fusaka can be launched as planned by the end of 2025, it will bring another round of orders of magnitude improvement to the L2 data space. L2 transaction fees may be further reduced in the next 1-2 years, thereby consolidating Ethereum's position in front of its competitors.

The continued expansion logic of the Ethereum roadmap

As we all know, Ethereum’s scalability problem was once the core bottleneck that caused the high cost of mainnet chain and the difficulty in popularizing DApps.

According to the data publicly shared by Vitalik in April this year, the current throughput of Ethereum L1 is 15 transactions per second, and the Gas limit has recently been increased to 36 million, an increase of about 6 times in the past 10 years.

At the same time, more significant changes have occurred in Ethereum L2. The current L2 throughput has reached about 250 TPS, and significant progress has been made in scalability. This capability is not limited to book data. Many users have also clearly felt the reduction in fees and the acceleration of on-chain operations:

Over the past year, whether it is Arbitrum, Optimism or Base, L2 transfer fees have generally dropped to the US$0.01 range or even lower, a drop of one or even multiple orders of magnitude compared to the previous period. The daily Gas cost of the Ethereum mainnet has also become significantly more friendly (of course, the impact of market conditions and on-chain activity is not ruled out).

This transformation is not accidental, but the result of Ethereum's strict adherence to the roadmap and continuous iteration. We can briefly review the key upgrades of the Ethereum network in recent years:

In 2022, Ethereum successfully switched to the PoS mechanism through The Merge upgrade.
Greatly reduces energy consumption and frees up execution layer bandwidth for subsequent upgrades;
In 2024, the Dencun upgrade was successfully activated and the Blob data mechanism was introduced.

Provides low-cost, temporary storage space for L2, which reduces the cost of Rollup and opens the way for scalability;

The recent Pectra upgrade was successfully launched on May 7, which greatly optimized the validator operation process and enhanced the flexibility of participating in the PoS system.

The next step, Fusaka upgrade, is the key step to continue the above process.

According to the latest statement by Tomasz Kajetan Stańczak, co-executive director of the Ethereum Foundation, Fusaka will be launched on the mainnet in the third or fourth quarter of 2025 (time to be finalized), and plans to implement multiple core EIPs including PeerDAS data availability sampling, further promoting Ethereum from performance bottlenecks to mainstream applicability.

It can be said that from The Merge → Dencun → Pectra → Fusaka, Ethereum is moving steadily towards its long-term blueprint, which is to build a global network that is secure, scalable, decentralized and sustainable.

Fusaka Upgrade Panorama

Judging from the 12 core EIPs included in this upgrade, it basically covers multiple technical dimensions such as data availability, node lightweighting, EVM optimization, and execution layer and data layer coordination mechanism.

Among them, the most popular proposal in this Fusaka upgrade is EIP‑7594 (PeerDAS), which introduces the "Data Availability Sampling (DAS)" mechanism, allowing validators in the network to complete verification by downloading only part of the Blob data without having to store all the data in full.

This greatly reduces the burden on the network, improves verification efficiency, and paves the way for L2's large-scale transaction processing capabilities. The concept of "Blob" here can be traced back to EIP-4844 introduced in the Dencun upgrade in 2024.

As the most important milestone of Ethereum in 2024, Dencun's upgraded EIP-4844 enabled transactions carrying blobs for the first time, allowing L2s to choose not to use the traditional calldata storage mechanism, thereby greatly improving the Gas fees required for transactions and transfers on L2.

So what is a Blob transaction? In short, it is to embed a large amount of transaction data into a Blob, which can significantly reduce the storage and processing burden of the Ethereum mainnet, not included in the Ethereum mainnet state, directly solve the L1 cost problem related to data availability, and ensure that the L2 platform can provide cheaper and faster transactions without affecting the security and decentralization based on Ethereum.

The Blob capacity expansion here is also based on Pectra - the Pectra upgrade in May has increased the Blob capacity from 3 to 6. It is worth mentioning that Vitalik has publicly stated that ideally, Fusaka will expand the Blob capacity to 72/block (first increase it to 12~24 in stages). If DAS is fully implemented in the future, the theoretical maximum capacity can reach 512 Blobs/block.

Once implemented, L2's processing power (TPS) is expected to leap to tens of thousands, which will greatly improve the availability and cost structure of high-frequency interaction scenarios such as on-chain DApps, DeFi, social networks, and games. This is also one of the core directions of the "L2 Security and Finalization Roadmap" previously proposed by Vitalik.

At the same time, Fusaka also plans to lightweight the state and node structure by introducing the Verkle tree, which will not only significantly compress the size of state proofs, making light clients and stateless verification possible, but also help promote the decentralization of Ethereum and its popularization on mobile terminals.

In addition, Fusaka also focuses on the flexibility and performance bottlenecks of the virtual machine layer (EVM), including the following proposals:

EVM and contract optimization rely on EIP‑7939 (CLZ opcode): efficient bit operations and accelerated cryptographic operations;
EIP‑7951 (secp256r1 replacement support): Improve compatibility with Web2 and enterprise architectures;
EIP‑7907: Expand the upper limit of contract size, support the deployment of more complex logic, and improve developer flexibility;

In order to ensure that the expansion does not affect the stability of the network, Fusaka also introduced EIP‑7934 to set a block size limit to ensure that the block will not be too heavy due to the expansion of Blob capacity, and adjusted the Blob usage fee through EIP-7892 / EIP-7918 to prevent resource abuse and dynamically match supply and demand fluctuations.

The watershed moment for Ethereum expansion and experience?

If we look at the whole picture, we will find that Fusaka is not only a technological upgrade, but also has the potential to lay a bridge from "scalability to availability" at multiple key levels.

For example, for Rollup developers, it means lower data writing costs and more flexible interaction space; for wallets and infrastructure providers, it means supporting more complex interactions and heavier-loaded node environments; for end users, it means experiencing on-chain operations with lower costs and faster responses; for enterprises and compliant users, EVM expansion and simplified state proofs will also make on-chain interactions easier to connect to regulatory systems and deploy on a large scale.

However, we still need to remain cautiously optimistic. As of the time of writing, Fusaka is still being tested on multiple Devnets, and the final launch time is still subject to change. In an optimistic scenario, Fusaka is expected to complete the mainnet deployment by the end of 2025, which may become another important milestone in Ethereum history after The Merge.

Overall, Fusaka is not only limited to the enhancement of on-chain scalability, but also represents a key step in Ethereum's transition to mainstream commercial applications and ordinary users. It is expected to provide a technical foundation for the next stage of Rollup ecology, enterprise-level Dapp, and on-chain user experience.

The real watershed for Ethereum’s move toward large-scale mainstream application may be approaching.