Ethereum Fusaka Upgrade Analysis: The Scaling Evolution Behind 12 EIPs

On June 20, at the 214th Ethereum execution layer core developer meeting (ACDE), the developers agreed to keep the final scope of the Fusaka upgrade basically unchanged, only adding an additional EIP (EIP 7939), bringing the total to 12 EIPs. This marks the official transition of Fusaka from the "planning" stage to the "implementation" stage.

As the largest hard fork bundled upgrade since The Merge, the market generally expects that if Fusaka can be launched as planned by the end of 2025, it will bring significant improvements to the L2 data space. The transaction fees for L2 may further decrease in the next 1-2 years, thereby consolidating Ethereum's competitive advantage.

The Continuous Evolution of the Ethereum Scalability Roadmap

The scalability issue of Ethereum has been a major barrier to the high on-chain costs of the mainnet and the widespread adoption of DApps. According to data shared by Vitalik in April this year, the current throughput of Ethereum L1 is 15 transactions per second, and the Gas limit has recently increased to 36 million, which is about a sixfold increase over the past 10 years.

More significant changes are taking place in Ethereum L2. Currently, the L2 throughput has reached about 250 TPS, achieving noticeable progress in scalability. Many users have already felt the reduction in costs and speed of on-chain operations: over the past year, the transfer fees of multiple L2 networks have generally dropped to the range of $0.01 or even lower, representing a decrease of one or even multiple orders of magnitude compared to before.

This transformation is the result of Ethereum strictly following its blueprint and continuously iterating on its roadmap. Looking back at the key upgrades of the Ethereum network in recent years:

• The Merge upgrade in 2022 transitioned to the PoS mechanism, significantly reducing energy consumption and freeing up execution layer bandwidth for subsequent upgrades.
• The Dencun upgrade will be activated in 2024, introducing a Blob data mechanism to provide low-cost temporary storage space for L2, significantly reducing Rollup costs.
• The latest Pectra upgrade went live on May 7th, optimizing the validator operation process and enhancing the flexibility of the PoS system.

The Fusaka upgrade is a key step in continuing this process. According to senior officials from the Ethereum Foundation, the Fusaka plan is set to launch the mainnet in the third or fourth quarter of 2025, which will implement several core EIPs, including PeerDAS data availability sampling, further pushing Ethereum to break through performance bottlenecks and move towards mainstream applications.

From The Merge to Dencun, Pectra, and then to Fusaka, Ethereum is steadily advancing its long-term blueprint aimed at building a global network that combines security, scalability, decentralization, and sustainability.

Fusaka Upgrade Overview

This upgrade includes 12 core EIPs, covering multiple technical dimensions such as data availability, node lightweighting, EVM optimization, and collaborative mechanisms between the execution layer and data layer.

The most notable is EIP-7594 (PeerDAS), which introduces the "Data Availability Sampling (DAS)" mechanism. This mechanism allows validators in the network to complete verification by downloading only a portion of the Blob data, without the need to store all data in full. This significantly reduces the network burden, improves verification efficiency, and paves the way for the large-scale transaction processing capability of L2.

The concept of Blob originates from EIP-4844 in the Dencun upgrade of 2024. As the most significant milestone for Ethereum in 2024, the Dencun upgrade introduced transactions carrying Blobs for the first time, allowing L2 to choose not to use the traditional calldata storage mechanism, thereby significantly improving the Gas fees required for transactions and transfers on L2.

Carrying Blob transactions embeds a large amount of transaction data into the Blob, significantly reducing the storage and processing burden on the Ethereum mainnet, not counting towards the mainnet state, and directly addressing the L1 cost issues associated with data availability. This ensures that L2 platforms can provide cheaper and faster transactions without compromising the security and decentralization of Ethereum.

It is worth noting that the Pectra upgrade in May has increased the Blob capacity from 3 to 6. Vitalik has stated that ideally, Fusaka will expand the Blob capacity to 72 per block (initially it may grow to 12-24). In the future, if DAS is fully implemented, the theoretical maximum capacity could reach 512 Blobs per block.

Once implemented, the processing capacity (TPS) of L2 is expected to soar to tens of thousands. This will significantly enhance the usability and cost structure of high-frequency interaction scenarios such as on-chain DApps, DeFi, social networks, and games, aligning with Vitalik's previously proposed "L2 security and finality roadmap" core direction.

At the same time, Fusaka also plans to achieve lightweight state and node structure by introducing Verkle trees. This not only significantly compresses the size of state proofs, making light clients and stateless verification possible, but also helps promote the decentralization of Ethereum and the popularity of mobile platforms.

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

• EIP-7939 (CLZ opcode): Efficiently implements bit operations, accelerates cryptographic computations
• EIP-7951 (secp256r1 alternative support): Enhancing compatibility with Web2 and enterprise architectures.
• EIP-7907: Expanding the contract size limit to support the deployment of more complex logic, enhancing developer flexibility.

To ensure that scalability does not affect network stability, Fusaka has introduced EIP-7934 to set block size limits, preventing blocks from becoming too heavy due to Blob expansion. At the same time, EIP-7892 and EIP-7918 have been implemented to adjust Blob usage fees, preventing resource abuse and dynamically matching supply and demand fluctuations.

The Turning Point of Ethereum Scalability and User Experience

Overall, Fusaka is not just a technological upgrade, but is also expected to lay the foundation for "from scalability to usability" on multiple key levels.

For Rollup developers, this means lower data writing costs and more flexible interaction space. For infrastructure providers, it means supporting more complex interactions and heavier load node environments. End users will experience lower costs and faster responses for on-chain operations. For enterprises and compliant users, EVM scaling and state proof simplification will make on-chain interactions easier to integrate with regulatory systems and large-scale deployments.

However, we still need to remain cautiously optimistic. As of now, Fusaka is still being tested on multiple testnets, and the final launch date may change. In an optimistic scenario, Fusaka is expected to complete its mainnet deployment by the end of 2025, which could mark another significant milestone in Ethereum's history following The Merge.

Overall, Fusaka is not only limited to enhancing on-chain scalability but also represents a crucial step for Ethereum's transition to mainstream business applications and ordinary users. It is expected to provide a technical foundation for the next stage of the Rollup ecosystem, enterprise-level Dapps, and on-chain user experience.

The true turning point for Ethereum's move towards large-scale mainstream applications may be approaching.