What is the Ethereum Fusaka Uprade?

The Ethereum Fusaka Upgrade is a planned network update that will follow the Pectra release. The name "Fusaka" combines "Fulu," a star from the Cassiopeia constellation, and "Osaka," a host city of a past Devcon event, keeping the tradition of naming consensus and execution layer upgrades after stars and cities.

Fusaka will focus on improving scalability and the developer experience on Ethereum. Major updates include PeerDAS through EIP-7594, which lets nodes sample small parts of data instead of downloading full datasets, and the Ethereum Object Format (EOF) for more secure and efficient smart contracts.

Fifteen Ethereum Improvement Proposals (EIPs) that were delayed from Pectra will also be part of Fusaka, with special attention on upgrading the Ethereum Virtual Machine (EVM). These changes will make Ethereum more effective as a data availability platform, supporting faster Layer 2s and decentralized applications.

Key Benefits of the Fusaka Upgrade

The Fusaka upgrade brings a critical focus on smart contract reliability, reflecting lessons learned from earlier Ethereum upgrades. It introduces technical changes that will shape Ethereum’s ability to handle heavier workloads and smarter transaction processing over the next several years.

Key benefits include:

• Blob Sampling Efficiency (PeerDAS): Reduces bandwidth and hardware strain on consensus layer nodes by allowing partial blob downloads instead of full data pulls.
• Higher Blob Throughput Targets: Sets the groundwork to raise Ethereum's blob capacity from 12 to potentially 50 blobs per block, drastically increasing Layer 2 transaction throughput.
• Predictable Smart Contract Execution (EOF): Overhauls how smart contracts are structured and validated within the EVM, making behavior more transparent and less prone to execution bugs.
• Faster Fork Parameter Changes (EIP-7892): Introduces blob parameter-only (BPO) forks for simple upgrades to blob settings, without requiring full hard forks each time adjustments are needed.
• Better Validator Coordination (EIP-7917): Enables deterministic proposer lookahead, letting validators know earlier who will propose blocks, which can improve consensus stability and pre-confirmations.

Ethereum Fusaka Release Date

Developers initially hoped to ship Fusaka by late 2025, following the activation of the Pectra upgrade on May 7th. However, based on the current development and testing timelines, the most realistic estimate for Fusaka's mainnet release is sometime in 2026.

The critical feature PeerDAS must be tested extensively across multiple devnets, and any setbacks in its stability could push the entire schedule. Additionally, developers have agreed to drop secondary features like EOF if needed to avoid further delays, showing that PeerDAS alone will dictate when Fusaka is ready.

Fusaka EOF and PeerDAS Explained

Two major components define the Fusaka upgrade: Ethereum Object Format (EOF) and Peer Data Availability Sampling (PeerDAS). Understanding how each of these works is key to grasping why Fusaka is so important for Ethereum’s future scalability and contract security.

What is EOF in Fusaka?

EOF (EVM Object Format), restructures smart contracts by introducing clear boundaries between code, data, and metadata, replacing the current unstructured bytecode model. This separation allows nodes to more easily validate contracts, leading to safer execution and lower gas costs at deployment.

The format is being delivered through a bundle of twelve coordinated EIPs, with the possibility of expanding to sixteen if progress remains steady. It marks the first deep structural change to the Ethereum Virtual Machine (EVM), paving the way for smoother future upgrades and optimizations.

Although EOF is currently scheduled for inclusion in Fusaka, its final status remains uncertain due to concerns about complexity and potential delays. Developers have emphasized that PeerDAS takes priority, and if necessary, EOF could be postponed to a future hard fork to protect Fusaka’s timeline.

What is PeerDAS in Fusaka?

PeerDAS (Peer Data Availability Sampling), allows consensus layer nodes to verify large blob transactions by sampling small random parts rather than downloading entire blobs. This method preserves data availability guarantees without demanding high bandwidth or heavy storage from node operators.

Through PeerDAS, Ethereum can dramatically boost blob throughput, with the network expected to handle up to 50 blobs per block over time. Developers have prioritized PeerDAS above all other Fusaka features because it is essential for scaling Ethereum to meet future Layer 2 and data-heavy application demands.

Ethereum Fusaka EIP List

The Fusaka upgrade includes a carefully curated list of EIPs that target Layer 1 scaling, Layer 2 data capacity, and smart contract developer experience. Based on updates tracked by Christine Kim, Vice President of Research at Galaxy Digital here are the Ethereum Improvement Proposal shaping Fusaka:

• EIP-7594: Introduces PeerDAS, a peer-to-peer sampling protocol allowing consensus nodes to verify blob data efficiently without full downloads, critical for Layer 2 scaling.
• EIP-7892: Enables Blob Parameter Only Forks, allowing automatic adjustments to Ethereum's blob transaction parameters through lightweight forks without full network upgrades.
• EIP-7692: Bundles twelve upgrades into Mega EOF, restructuring how smart contracts are stored, validated, and executed inside the Ethereum Virtual Machine.
• EIP-7917: Pre-computes block proposers several epochs in advance with Deterministic Proposer Lookahead, helping rollups and decentralized apps optimize Layer 2 sequencing.
• EIP-7825: Imposes a Transaction Gas Limit Cap of 30 million per transaction to prevent heavy operations from congesting the Ethereum network.
• EIP-7918: Ensures Blob Base Fee is Bounded by Execution Cost, promoting stable and predictable fee markets critical for Layer 2 scaling.
• EIP-7762: Raises the Minimum Blob Base Fee to maintain healthier data markets and reduce the risk of volatile pricing swings.

Several other EIPs, including EXTCODETYPE (EIP-7761), PAY Opcode (EIP-5920), and Meter Contract Size Limits (EIP-7907), are also under discussion but are seen as secondary to the core scaling. These additional proposals mainly improve contract flexibility, execution efficiency, and native EVM operations.

Will Fusaka Benefit ETH Investors?

Ethereum investors have faced a long period of mixed results, with ETH still trading around $1,800 today, far below its $4,724 all-time high from late 2021. Since the Merge, ETH is up 42.4%, but since the Dencun upgrade, it has fallen 55.3%, highlighting the ongoing struggle for strong post-upgrade momentum.

Ethereum’s fundamentals have also weakened, with TVL dropping from $75 billion to $51 billion and daily fees collapsing from over $40 million to <$1 million. Cardano’s Charles Hoskinson warned that without meaningful upgrades, Ethereum could face a slow decline into irrelevance over the next 10 to 15 years.

However, Fusaka and Pectra may offer a turning point, introducing PeerDAS, EOF, and a possible 4x gas limit increase to boost Layer 1 performance. If these upgrades succeed, they could reset Ethereum’s competitiveness and rebuild long-term investor confidence.

What are the Risks of the Fusaka Upgrade?

The Fusaka upgrade carries several risks that could impact Ethereum’s security, reliability, and timeline if not carefully managed. These risks mainly stem from the technical complexity of PeerDAS, the depth of EOF changes, and the challenge of coordinating client teams.

Key risks for Ethereum Fusaka include:

• PeerDAS implementation issues: If data sampling fails to fully guarantee blob availability, Ethereum’s data reliability model could weaken under high network load.
• EOF migration problems: The overhaul of smart contract structure could introduce critical bugs during deployment or cause unpredictable behavior in legacy applications.
• Testnet and upgrade delays: Misaligned client upgrades or instability during devnet and public testnet phases could easily push Fusaka’s mainnet date deeper into 2026.
• Scope creep from new EIPs: Adding too many "considered for inclusion" EIPs could overcomplicate testing, slow developer focus, and raise the chance of undetected errors.
• Client coordination challenges: Fusaka requires flawless updates across both consensus and execution layers, increasing the difficulty compared to simpler past upgrades.
• Rollback difficulty: Fixing or reversing critical Fusaka changes post-launch would be extremely hard, especially if bugs are buried inside PeerDAS or EOF structures.

Final Thoughts

Fusaka represents one of the most ambitious upgrades in Ethereum’s history, but ambition alone won't guarantee success. The coming months will test whether Ethereum’s developers and users can deliver on bold promises while maintaining the network’s stability.

If executed well, Fusaka could mark the start of a new era for Ethereum investors, but the margin for error is thinner than ever. We are watching closely to see if Ethereum can rise to the challenge.