TLDR
- The Fusaka update will activate on Ethereum’s mainnet on December 3rd, 2025, following a testnet rollout starting October 1st, 2025.
- The update will introduce a phased blob capacity expansion to improve data handling and Layer 2 rollup scalability.
- PeerDAS implementation through EIP-7594 will reduce bandwidth and storage requirements for validator nodes.
- The upgrade will create predictable transaction costs for data-heavy applications through bounded base fees for blob transactions.
- Fusaka focuses on enhancing Ethereum’s scalability, node efficiency, and data availability rather than adding user-facing features.
Ethereum’s highly anticipated Fusaka update will activate on the mainnet on December 3rd, 2025. The upgrade follows a testnet rollout starting on October 1st, 2025, with Holesky leading the way. Developers have confirmed that Fusaka will implement significant improvements in scalability, node efficiency, and data availability.
Phased Blob Capacity Expansion Through Fusaka Update
The Fusaka update will prioritize backend protocol improvements. It introduces a phased blob capacity expansion with Blob Parameter Only (BPO) forks. The first BPO fork will increase capacity to 10/15 blobs, activating December 17, 2025. A second BPO fork will follow on January 7, 2026, further expanding capacity to 14/21 blobs.
Ethereum developers emphasized that Fusaka will enhance the network’s data handling capacity. The increase in blob capacity will improve Layer 2 rollup scalability. Christine Kim, an Ethereum developer, stated that the phased approach offers greater flexibility for expanding blob limits.
The Fusaka update is designed to support higher transaction volumes. It reduces bandwidth and storage demands, making Ethereum more efficient. This will enable Ethereum to handle more transactions without compromising security or decentralization.
Improved Efficiency with PeerDAS and EIP-7594 in Fusaka Update
Another crucial aspect of the Fusaka update is the introduction of PeerDAS through EIP-7594. This innovation allows validator nodes to verify data by sampling small pieces instead of downloading entire blobs. This reduces bandwidth and storage needs, improving overall node efficiency.
The implementation of PeerDAS will also support Ethereum’s scalability, particularly for Layer 2 rollups. The upgrade aims to lower barriers for smaller operators, enhancing decentralization. Ethereum’s infrastructure will become more accessible and efficient for developers and validators alike.
At a high-level, here’s what developers agreed should be the schedule for Fusaka moving forward:
October 1: Holesky upgrade
October 14: Sepolia upgrade
October 28: Hoodi upgrade
December 3: Mainnet upgrade— Christine D. Kim (@christine_dkim) September 18, 2025
The Fusaka update also includes EIP-7918, which introduces bounded base fees for blob transactions. This will help create predictable transaction costs for data-heavy applications. As a result, Ethereum’s transaction model will become more reliable and transparent.
Ethereum Aims for 2,000 Transactions Per Second
The Fusaka upgrade comes in the wake of Ethereum’s ongoing scalability efforts. Recent gas limit increases from 30 million to 45 million gas set the stage for higher transaction throughput. With EIP-7935 proposing a further increase to 150 million gas, Ethereum is on track for significantly higher transaction capacity.
While Fusaka mainly focuses on infrastructure improvements, it will lay the foundation for future upgrades. Discussions around a 100x gas limit increase through EIP-9698 suggest Ethereum could eventually handle 2,000 transactions per second. These improvements aim to meet the growing demand for Ethereum’s scalability without compromising its decentralized nature.
The Fusaka update addresses critics who have pointed out the fragmentation of Ethereum’s Layer 2 solutions. By strengthening the base layer, Ethereum ensures better interoperability between chains. Ethereum’s focus on foundational improvements will support continued Layer 2 growth in the long term.