Ethereum Fusaka Upgrade: Blob Capacity Raised 8x and Layer 2 Fees Collapse
Ethereum's Fusaka upgrade, activated December 3, 2025, raised blob capacity from 6 to 48 per block and lifted the gas cap to 150 million. The result: Layer 2 transaction fees fell by more than 80% and DeFi throughput surged across Arbitrum, Optimism, Base, and Scroll.
Quick answer
Ethereum's Fusaka upgrade, activated December 3, 2025, raised blob capacity from 6 to 48 per block and lifted the gas cap to 150 million. The result: Layer 2 transaction fees fell by more than 80% and DeFi throughput surged across Arbitrum, Optimism, Base, and Scroll.
What Fusaka changed
Ethereum's Fusaka hard fork activated on December 3, 2025 at epoch 364,032. The upgrade's most impactful change was EIP-7691: raising the target blob count from 3 to 6 per block and the maximum from 6 to 48 — an 8x increase in blob throughput capacity.
Blobs — introduced by EIP-4844 (Dencun) in March 2024 — are the primary data availability mechanism for Ethereum rollups (Arbitrum, Optimism, Base, zkSync, Scroll, Starknet). Rollups post compressed transaction data as blobs, which are stored on Ethereum for approximately 18 days before being pruned. Before Fusaka, blob space was frequently congested during peak periods, driving up L2 fees.
Fusaka also raised the gas limit to 150 million (from 36 million at the start of 2024), significantly increasing Ethereum mainnet throughput — although mainnet is no longer the primary execution layer for most DeFi activity.
The fee collapse on Layer 2s
The effect on Layer 2 costs was dramatic. Within one week of Fusaka, average transaction fees on Arbitrum fell from approximately $0.05 to under $0.005. Base's fees dropped similarly. On Starknet and Scroll, fees reached fractions of a cent — making on-chain DeFi economically accessible for the first time for small-value transactions.
DeFi throughput responded immediately. Uniswap V4 daily transactions on Arbitrum and Base increased 340% in the two months following Fusaka. Aave saw a 180% increase in smaller loan originations under $10,000 — a segment previously priced out by gas costs. NFT minting volumes on Base tripled.
The Ethereum developer community has set ambitious targets for further blob increases in the Glamsterdam upgrade planned for late 2026, which aims to raise maximum blobs to 128 per block and introduce full data availability sampling.
Ethereum's evolving role
Fusaka accelerates Ethereum's transition from a monolithic blockchain to a modular settlement and data availability layer. Ethereum mainnet increasingly serves three functions: settlement of rollup state roots (the authoritative record of Layer 2 state), data availability for rollup transaction data (blobs), and the primary home for the highest-value DeFi markets where mainnet's security premium justifies higher fees.
This architecture positions Ethereum as infrastructure rather than execution environment — a design that Ethereum researchers argue maximises long-term security and decentralisation while offloading everyday transactions to specialised execution layers.
ETH's economic model benefits from this structure: blob fees are burned (EIP-1559), adding deflationary pressure proportional to L2 activity. Higher rollup usage means more ETH burned from blob fees, even without mainnet congestion.
Frequently Asked Questions
What happened with Ethereum Fusaka Upgrade?
Ethereum's Fusaka upgrade, activated December 3, 2025, raised blob capacity from 6 to 48 per block and lifted the gas cap to 150 million. The result: Layer 2 transaction fees fell by more than 80% and DeFi throughput surged across Arbitrum, Optimism, Base, and Scroll.
Why does this matter for DeFi?
Events like this affect the broader DeFi ecosystem by influencing market sentiment, regulatory expectations, protocol adoption, and on-chain activity. Understanding the context helps investors and users make more informed decisions about their exposure to decentralised finance protocols.
How does this affect crypto investors?
Significant DeFi developments — whether protocol upgrades, regulatory actions, or market milestones — can shift capital flows, yield opportunities, and risk profiles across the ecosystem. Staying informed through credible sources is essential for risk management in DeFi.
Where can I learn more about Ethereum?
Our Ethereum research section covers protocols, ecosystems, and market developments in depth. Visit the relevant protocol or ecosystem page on this site for background context, or browse the DeFi Glossary for plain-English definitions of key terms.
Is this news verified?
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