Ethereum is a continuously evolving blockchain network that has many past upgrades like The Merge, Shanghai/ Capella, Dencun and the recent Pectra all of which laid the groundwork for scalability and efficiency. The Fusaka upgrade was named by combining “Osaka” the execution layer and “Fulu” the consensus layer internal project name. It is a major hard fork scheduled for mainnet activation on December 3, 2025. This upgrade represents the largest bundled upgrade since The Merge, and it is packed with 12 Ethereum Improvement Proposals (EIP) aimed at enhancing scalability for user experience. Fusaka focuses on full data scaling, optimizing costs and preparing Ethereum for mainstream adoption, which ultimately expands its capacity.
It is important to note that Fusaka testnets ran in Oct/Nov 2025 and the community set a mainnet rollout target for December 3, 2025.
What Fusaka actually changes
Fusaka’s EIP-7594 or PeerDAs is a network level Data Availability sampling protocol that lets nodes sample small authenticated “cells” of data blobs instead of downloading full blobs. This sampling system enables higher blob throughput without blowing up node bandwidth/storage. As a result of this development the L1 Ethereum layer can safely accept many more L2 data blobs per block.
Fusaka’s Verkle Tree plus precompile EIP-7545 and related replaces and augments Merkle Patricia structures with Verkle commitments to shrink state proof sizes dramatically. This enables lighter stateless clients and faster light client validation for mobile and edge clients benefits.
The Fusaka upgrade also includes EIPs that raise the default safe block gas limit. The EIP-7935 sets a new default to 60M in the Fusaka spec and implements transaction level gas caps. This and other execution tweaks enable higher L1 execution capacity without single-tx DoS risk.
In addition to all this, the Fusaka upgrade brings controlled, short follow forks to raise blob target/ max safely after PeerDAS is active.
PeerDAS EIP-7594 explained
PeerDAS or peer to peer data availability sampling is a core innovation in the Fusaka upgrade as it introduces a new networking protocol for Data Availability Sampling (DAS). Unlike previous methods where every validator had to download full transaction data, PeerDAS allows validators to probabilistically sample small portions of blob data. They then cryptographically reconstruct and verify data, and this significantly reduces individual bandwidth and storage demands for nodes.
This mechanism dramatically boosts data throughput, enabling rollups to handle over 100000 transactions per second. Crucially, PeerDAS is expected to cut L2 transaction fees by an estimated 50-70%, with some projections suggesting reductions of 75-95%. The massive cost reduction makes Ethereum’s L2 ecosystem far more competitive and accessible.
Verkle trees explained
Verkle Trees are cutting edge cryptographic data structures that combine “vector commitments” and “Merkle Trees”. They are designed to create smaller and more efficient proofs for verifying the Ethereum state. Verkle trees are a critical step towards “stateless Ethereum clients.” Currently, to run an Ethereum node data must be stored in a large amount of state data. With Verkle, there is no need for nodes to store entire state databases. Instead, they verify blocks using tiny witnesses which are cryptographic proofs that confirm data without requiring the full dataset. This dramatically reduces witness sizes from approximately 150 KB to just 1-2 KB per proof.
This innovation lowers the hardware requirements and entry barriers for running an Ethereum node. It empowers more individuals to operate full nodes, thereby increasing the network’s decentralization and security. This ensures that Ethereum remains robust and censorship resistant.
Why this is very important for AI driven apps
The Fusaka upgrade is especially important to AI apps for several reasons. For one, AI apps are data heavy containing embeddings, vector indices, model checkpoints, telemetry and inference logs. All these can be very bandwidth and storage intensive. With the Fusaka upgrade, it becomes easier and many times cheaper to put large data or proofs/commitments on L2s when L1 blob space and DAS scale. PeerDAS is a direct successor to EIP-4844 Proto-Danksharding which introduced blobs in the Dencun upgrade of March 2024. Proto Dankcharding made L2 transactions cheaper by introducing a new temporary data type for roll ups. PeerDAS implements the full DAS mechanisms needed to securely scale blob capacity further. This paves way for full Danksharding.
Fusaka upgrade also brings concrete mechanisms by providing cheaper blob capacity and PeerDAS. This lowers per byte data availability fees which are passed to rollups. Rollups can then offer sub-cent writes for bulk data for example embedding writes or model checkpoints. This makes hybrid onchain/offchain AI workflows economically viable.
The Fusaka upgrades also brings Verkle effects as much smaller state proofs makes it feasible to run secure light clients on phones and edge devices. So, this means AI dApps can verify date/state locally without heavy infra which improves UX and decentralization.
AI driven decentralized applications often require significant data storage and complex computations which traditionally incurred high costs on Ethereum. By drastically reducing L2 transaction fees via PeerDAS and making data verification more efficient with Verkle Trees, the Fusaka upgrade directly lowers operational costs for AI applications.
Impact on DEXs vs CEXs
This upgrade would fuel growth in decentralized exchanges as Fusaka brings much lower settlement/data costs on rollups and also higher L1 throughput. Also, composability which includes atomic onchain settlement and permissionless liquidity composability, reduces the cost and latency penalty that historically favoured centralized matching. This can help in attracting spot traders and onchain liquidity providers as gas fees become sub-cent.
There is no doubt that the very cheap fees, improved data availability and faster transactions as well as enhanced node accessibility introduced by the Fusaka upgrade will make using DEXs on Ethereum and L”s more attractive than ever. This closing gap in user experience and cost effectiveness with CEXs is expected to accelerate the shift in trading volume, potentially leading to DEX volumes surpassing CEXs for the first time on a sustained basis.
On the other hand, custody and fiat rails, derivatives, KYC, regulatory settlements, off chain matching speed and deep liquidity concentration on few CEXs are structural advantages that gas or cost improvements alone cannot erase. For a genuine flip of CEXs, DEXs need trading volumes, good UX, fiat rails, custody solutions and regulatory clarity in addition to the lower on-chain costs. This can only happen in the long term, not short term.
Final thoughts and conclusion
It is important for Ethereum users to know that the Fusaka upgrade is not just a technical update, it's a strategic move that significantly enhances Ethereum’s capabilities for mass adoption. By making the network faster, cheaper and more decentralized, Fusaka solidifies Ethereum’s position as the foundation layer for the next generation of web 3 applications including AI driven dApps and a thriving on chain financial ecosystem. Future updates like the Glamsterdam targeted for 2026 will continue to build on these improvements.
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References
What Happens to Ethereum (ETH) After the Fusaka Upgrade? https://www.ccn.com/ethereum-eth-fusaka-upgrade-what-happens-next/
The State of Ethereum: Digital Oil, L2s, TPS, ETFs, DATs https://www.arkhamintelligence.com/blog/the-state-of-ethereum-digital-oil-l2s-tps-etfs-dats
Ethereum Fusaka Upgrade: All You Need to Know https://www.binance.com/en/feed/post/3673322129532
PeerDAS Explained: How Ethereum Will Make Crypto Fees Drop 50–70% in December 2025 https://medium.com/@blockbuilders/peerdas-explained-how-ethereum-will-make-crypto-fees-drop-50-70-in-december-2025-e0d4f3b1a8d0
DEX Volume Hits Record As Traders Leave Centralized Exchanges https://beincrypto.com/dex-volume-record-traders-centralized-exchanges/
