Ethereum Fusaka Upgrade

Jul 29, 2025 | Updated Oct 31, 2025

The Ethereum Fusaka upgrade is a network improvement that aims to dramatically increase Layer 2 data capacity and reduce transaction costs.

What Is the Ethereum Fusaka Upgrade?

The Ethereum Fusaka upgrade is an Ethereum hard fork that represents the network’s largest bundled upgrade since The Merge, containing 12 Ethereum Improvement Proposals (EIPs) designed to enhance scalability and user experience. Scheduled for late 2025, Fusaka follows the successful Pectra upgrade and aims to dramatically increase how much data Layer 2 networks can process, resulting in lower fees for users.

The upgrade builds upon the blob transaction framework introduced in the Dencun upgrade, potentially increasing data throughput by massive amounts. This could allow Layer 2 networks to handle tens of thousands of transactions per second, making Ethereum more accessible for everyday use.

How Does the Fusaka Upgrade Work?

The Fusaka upgrade implements several key improvements to make Ethereum more efficient. The centerpiece is PeerDAS (Peer-to-Peer Data Availability Sampling), which unlocks more scalability for rollups while maintaining the network’s security.

Put simply, it could allow for up to 8 times the blob space currently available. This allows for increased temporary data storage without putting more strain on the mainnet. Plus, it will also minimize the permanent data stored in nodes, allowing for a more streamlined chain. It may even reduce layer 2 transaction costs by reacting more efficiently to congestion.

These improvements move the Ethereum network towards competing with high-speed blockchains, and is also paving the way for full Danksharding.

Apart from PeerDAS, the Fusaka upgrade also makes a few minor changes to the EVM. Firstly, there will be changes to the maximum size of a single transaction to ensure security while scaling. Next, a new opcode will be introduced, offering a new function for smart contracts to become more efficient. Finally, the ModExp contract, which makes cryptographic operations used in cryptographic proofs and digital signatures, will charge more gas for execution.