Ethereum’s Fusaka Upgrade: Everything You Need to Know

On The Radar

Edyme

December 4, 2025

In conclusion

What is the Fusaka upgrade?

Ethereum just pulled off another network evolution. Fusaka went live a few hours back at slot 13,164,544.

Dencun laid the foundation in 2024, Pectra set the tempo earlier this year, and Fusaka is the upgrade that hits the accelerator.

Packed with 13 EIPs spanning scalability, security, developer tooling, and user experience, it basically restructures how Ethereum handles data, fees, and throughput. And yes, layer-2 fees really did plummet overnight.

PeerDAS, blob scaling, and the big throughput leap powered by Fusaka

At the center of Fusaka’s impact is PeerDAS (EIP-7594), a completely new way for Ethereum nodes to verify data availability for blobs, the data packets that rollups use to publish transactions onchain.

Previously, every node had to store each blob in full, which capped Ethereum at three blobs per block. But PeerDAS changes the rules: nodes now sample small parts of the data rather than store everything.

This single change unlocked:

Up to 24 blobs per block via initial Blob-Parameter-Only (BPO) fork
A roadmap to reach 128 blobs over time
A long-term path to 100,000+ TPS across the L2 ecosystem
40–60% L2 fees drop within the first month as PeerDAS activates and blob throughput scales, with further reductions (potentially 90%+) as the network ramps to higher blob counts in 2026.

To keep this scaling flexible, Fusaka adds Blob-Parameter-Only (BPO) forks (EIP-7892), letting Ethereum adjust blob limits without future hard forks. The next upgrades are already scheduled:

December 9, 2025: Max blobs → 15
Early January 2026: Max blobs → 21

Blob pricing also gets a fix via EIP-7918, which ties blob base fees to L1 gas demand, ensuring fees don’t drop to meaningless 1-wei levels, stabilizing rewards for validators and reducing spam from rollups.

Fusaka also doubles the standard block gas limit with EIP-7935, from 30M to 60M, letting Ethereum settle 20–30% more transactions while sustaining 50–100 TPS on the L1 alone.

L2 apps will still carry the throughput load, but the L1 is now significantly less congested.

Node efficiency, UX upgrades, and stronger security

Fusaka also brings major quality-of-life improvements for node operators, developers, and everyday users.

Node and developer improvements

EIP-7642 introduces history expiry notices, letting nodes efficiently announce the ranges of history they serve. Paired with the removal of outdated bloom filters, full sync times have dropped up to 40%, saving more than 500GB of storage during sync.
EIP-7910 adds a new JSON-RPC method, eth_config, so tools and wallets can automatically detect a node’s fork settings.

P-256 support for mass adoption

One of the most user-facing changes is secp256r1 (P-256) support (EIP-7951), the cryptography standard used by iOS, Android, and billions of devices. This lets wallets integrate native biometric signing (Face ID, fingerprint, etc.) without clunky custom code.

Mobile wallets running early builds are reporting:

Up to 50% faster signing times
Seamless biometric transactions
A notable onboarding improvement for mainstream users

Security hardening

Fusaka also ships several anti-DoS reinforcements:

EIP-7825 caps any single transaction at 16.7M gas, preventing block monopolization.
EIP-7934 enforces a 10MB RLP block size limit, stopping oversized payload attacks.
EIP-7823, EIP-7883, and EIP-7939 optimize precompiles and opcodes, eliminating underpriced operations that attackers previously exploited.

Developer tooling for faster apps

Opcode improvements like Count Leading Zeros (CLZ) trim bytecode size and reduce gas costs for hashing and ZK operations by 10–20%.

Updates to MODEXP ensure bounded inputs and fair pricing, speeding up ZK-rollup proving times by up to 15%.

Instant pre-confirmations

Additionally, EIP-7917 activates deterministic proposer lookahead, enabling validators to provide sub-second “soft confirmations,” bringing L1 UX closer to the instant feel of fast rollups.

The road ahead post Fusaka

Fusaka is now the backbone for Ethereum’s next growth cycle.

With cheaper rollups, more predictable gas, faster syncing, better security, and native biometric wallet support, the network is now positioned to scale from millions to hundreds of millions of users.

L2s get cheaper.

Builders get faster tools.

Users get smoother experiences.

Overall, Ethereum gets another performance jump without sacrificing decentralization.