Key Insights
- Fusaka expands Ethereum’s data capacity by way of PeerDAS and increased blob targets, lowering Layer-2 costs and supporting broader ecosystem growth.
- This upgrade increases Ethereum’s gas limit to 60 million, thus enabling higher throughput, improved transaction room, and smoother large-scale execution.
- New features including deterministic proposer lookahead, r1 curve support, and the CLZ opcode improve confirmation speed, security, and developer efficiency.
Ethereum activated its Fusaka (Fulu + Osaka) upgrade on December 3, delivering a coordinated set of changes designed to scale the network without compromise. The update strengthens data availability, raises execution capacity and introduces new cryptographic and developer-focused tools. Each component works toward a single direction: enabling Ethereum to grow while keeping security intact.
PeerDAS, Blob Expansion and Data Availability
Ethereum stated in its announcement that Fusaka’s central theme is scaling without compromise, and this begins with PeerDAS. The network emphasized that Peer Data Availability Sampling drives the increase in blob capacity while maintaining security guarantees. Nodes store one-eighth of blob data rather than full datasets, allowing more data throughput without placing heavy demands on participants.
https://x.com/ethereum/status/1996258202669695080?s=20
The introduction of Blob Parameter Only (BPO) upgrades allows the network to raise blob limits smoothly. Ethereum said the first BPO will increase targets to ten and a maximum of fifteen on December 9, with another step to fourteen and twenty-one scheduled for January 7, 2026. These controlled increases reduce Layer-2 costs, create more execution space and improve the ecosystem’s ability to handle rising activity.
Ethereum also noted that the blob base fee now operates under a bounded mechanism to keep costs predictable. Supernodes holding 4,096 ETH or more must store full blob data to preserve integrity. These adjustments support the broader objective of increasing throughput while preserving reliability for users, builders and infrastructure providers.
Gas Limit Expansion and Execution Improvements
In the execution ecosystem, Ethereum has confirmed the increase in gas limit with a new post announcing that it has increased from 45 million to 60 million which has increased capacity by ~33%. This added capacity allows for many more transactions per block as well as allows applications to perform greater computationally intensive operations with a higher degree of flexibility. Two additional tests have been done to verify the safety of conducting ModExp pricing at this higher gas limit.
Validators running the default client will now be validated with a gas limit of 60 million, however, updates to the configuration can be performed should a validator require an update to their configuration settings. Block proposers can still adjust the limit gradually as defined under EIP-1559, promoting stable block production. A new cap near 16.8 million gas per transaction requires developers using large interactions to ensure compatibility.
Execution-layer changes such as ModExp cost adjustments, the introduction of RLP execution block size limits and simplified receipts under eth/69 support the network’s increased load. Each adjustment aligns with the upgrade’s mission by improving consistency and maintaining performance under expanded throughput.
Cryptographic Enhancements and Low-Latency Preconfirmation
Fusaka also addresses security and usability through added cryptographic support. Ethereum recently added the ability to verify signatures on the native Secp256r1 curve to its blockchain with the introduction of its latest precompiled contract. As a result, the Ethereum network can now directly validate signatures generated from hardware that uses the secp256r1 curve, which is commonly found in Apple’s Secure Enclave, Google’s Android Key store, and password-protected devices. The interface follows RIP-7212 with added protections for edge cases.
Deterministic proposer lookahead is another feature supporting Ethereum’s scaling direction. With future block proposers known ahead of time, systems offering preconfirmation can reduce latency to milliseconds. This adjustment strengthens predictability and makes near-instant confirmation models easier to deploy.
The CLZ opcode also arrives with Fusaka, enabling developers to count leading zeros in binary formats with lower gas cost and smaller bytecode footprints. Solidity has already integrated the feature into its 0.8.31 pre-release, giving teams an early chance to experiment.
Configuration Tools and Test net Preparation
To maintain smooth coordination as the network grows, Ethereum added the ethconfig RPC method. This aspect enables the clients to report configuration information, which minimizes the chances of mismatch and allows the operators to check the upgrade preparedness. As part of scaling without compromise, transparent configuration reporting helps maintain operational stability during major transitions.
Before reaching main net, Fusaka completed extensive testing across multiple environments. Ethereum confirmed deployments on Holešky on October 1, Sepolia on October 14 and Hoodi on October 28. These stages validated functionality under diverse conditions. Although Holešky is now deprecated, it played a role in confirming Fusaka’s readiness.
With PeerDAS, expanded blob capacity, higher gas limits, improved cryptographic support and new developer tools, the Fusaka upgrade pushes Ethereum further into its next phase of scaling without compromise.
