What is the Ethereum Fusaka upgrade?

Fusaka combines "Fulu" for the consensus layer and "Osaka" for the execution layer, making it Ethereum's second major upgrade of 2025 after Pectra. It was activated on mainnet on December 3, 2025, bundling around 13 EIPs focused on scaling data availability, improving L1 execution efficiency, and developer tooling.

How does the Fusaka upgrade improve Ethereum scalability?

PeerDAS (EIP-7594) lets nodes verify rollup data by sampling random chunks rather than downloading entire blobs, cutting bandwidth while enabling higher throughput. EIP-7935 raises the default block gas limit from 45 million to around 60 million. BPO forks then allow blob capacity to increase gradually between named hard forks.

What is data availability and why is it important in Fusaka?

Data availability means all transaction data posted to Ethereum can be verified as accessible, a prerequisite for secure rollup operation. L2s like Arbitrum and Base post compressed batches as blobs on Ethereum. PeerDAS scales this by having each node check only a fraction of blob data rather than storing it all.

How will the Fusaka upgrade impact ETH price and tokenomics?

EIP-7918 sets a reserve price floor preventing blob fees from collapsing to near-zero during quiet periods, a problem that made ETH inflationary throughout much of 2025. This generates consistent fee burns under EIP-1559. Traders looking to express views on ETH's post-Fusaka trajectory can access options and futures on Delta Exchange.

What are the risks associated with the Ethereum Fusaka upgrade?

Hard forks carry consensus risk if client implementations diverge, though Fusaka ran successfully across Holesky, Sepolia, and Hoodi testnets before mainnet. PeerDAS introduces new networking behaviour that may surface edge cases under real load. EIP-7918's fee floor also creates new market dynamics L2 sequencers and traders on Delta Exchange will need to model.

Delta Exchange Blog

Educational

Ethereum Fusaka Upgrade: Everything You Need To Know

Shubham Goyal

December 10, 2025