Ethereum Fusaka Upgrade Definition

The Ethereum Fusaka upgrade is a hard fork that packages several protocol changes to make the network handle more data at lower cost, especially for Layer 2 rollups. It is described as the biggest bundled update since the Merge, with a set of EIPs aimed at scaling and a smoother user experience.

Gas policy changes

Fusaka introduces a cap on how much gas a single transaction can use, set at around 16.78 million units. The goal is to stop one transaction from dominating an entire block, reduce denial-of-service risk, and make block composition more predictable. Alongside this, developers are raising the network’s default block gas limit on testnets to about 60 million as part of the rollout. Some educational material also describes a target increase to 150 million for the mainnet. These adjustments are also framed as preparation for future parallel execution.

Data availability with PeerDAS

A headline feature of Fusaka is Peer Data Availability Sampling, or PeerDAS. Rather than downloading whole blob datasets, validators check small random samples shared by peers. This keeps security assumptions while easing bandwidth and storage needs, which helps rollups post more data at lower cost.

Verkle trees and state proofs

Fusaka also introduces Verkle trees for a more compact way to prove parts of Ethereum’s state. The structure allows smaller proofs and faster verification, which helps keep node requirements manageable as chain data grows.

Who benefits from the upgrade?

• Users see steadier fees and fewer slowdowns during busy periods because blocks fit more activity and transactions are spread more evenly.
• Developers on Layer 2s get more blob capacity and cheaper data posting, which improves throughput for dapps.
• Validators and node operators handle less data per verification step thanks to sampling, although some hardware and configuration updates may be needed.

Place in the roadmap

Fusaka follows Dencun and Pectra on Ethereum’s long-term roadmap. The per-transaction gas cap and throughput tweaks are described as steps that pave the way for future upgrades focused on parallel execution.