Ethereum Fusaka Upgrade Successfully Activates on Mainnet Bringing Major Scaling Improvements

The most significant upgrade for Ethereum of 2025, known as Fusaka, officially launched on the mainnet this week. The hard fork activated at exactly 9:49 p.m. UTC during Epoch 411392, marking another milestone in the network’s long-term scaling roadmap. Developers, node operators, and layer-2 teams had been preparing for months, and the activation proceeded without reported issues across major clients.

The upgrade introduces several technical enhancements designed to make Ethereum faster, cheaper, and more resilient for everyday users and large-scale applications. Lower transaction costs, higher data capacity for rollups, and better protections against network congestion now form the new baseline for the world’s leading smart contract platform. These changes collectively push Ethereum closer to the performance levels needed for mainstream adoption.

PeerDAS and New Transaction Limits Drive the Upgrade Forward

The centerpiece of Fusaka is Peer Data Availability Sampling, or PeerDAS, which dramatically increases the amount of data layer-2 networks can publish to Ethereum while keeping costs manageable. By splitting large data blobs into smaller cells and allowing nodes to sample only the portions they need, PeerDAS enables up to eight times more throughput for rollups compared to the previous Dencun-era system. This boost translates directly into lower fees and higher transaction volume capacity for popular layer-2 chains such as Arbitrum, Optimism, Base, and zkSync.

Another important change comes from EIP-7825, which sets a per-transaction gas limit of approximately 16.78 million gas units starting with Fusaka. Before this rule, a single complex transaction could theoretically consume an entire block’s gas limit of around 45 million, creating denial-of-service risks and complicating future parallel execution plans. The new cap ensures blocks contain multiple smaller transactions, improving predictability and paving the way for upcoming upgrades like Glamsterdam that will process transactions in parallel.

Most ordinary users will notice no difference in their day-to-day activity, as the vast majority of wallet transfers, token swaps, and NFT mints already use far less than 16 million gas. Developers working with batch processing contracts or large deployment scripts, however, may need to split their operations into multiple transactions to stay under the limit. The Ethereum Foundation published details earlier this week to help affected projects adjust smoothly.

With PeerDAS live and the transaction cap in place, the foundation emphasized that Fusaka lays critical groundwork for near-instant transaction feel across the ecosystem. Combined with based preconfirmations and ongoing layer-2 improvements, users can expect confirmation times to drop from minutes to milliseconds in many cases. These speed gains, paired with sustainably lower costs, position Ethereum to handle significantly higher demand without sacrificing decentralization or security.

The successful Fusaka activation keeps Ethereum on track with its 2025-2026 roadmap, often referred to as “The Surge” phase of scaling. Upcoming hard forks will build on these foundations by introducing full parallel execution, even higher blob counts, and additional data-availability enhancements. For now, the network has taken a major step forward in delivering the performance that developers and users have been waiting for since the transition to proof-of-stake.