Ethereum co-founder Vitalik Buterin has outlined a new roadmap for scaling the Ethereum network, focusing on the often-overlooked process of block building and the potential for centralization within it. In a blog post Monday, Buterin detailed proposals aimed at ensuring a more decentralized and resilient system as Ethereum processes increasing transaction volumes.
The proposals approach as Ethereum prepares for the “Glamsterdam” upgrade, scheduled for the first half of 2026, which will implement proposer-builder separation (PBS). PBS allows validators – those who confirm transactions – to outsource the construction of blocks to specialized builders, creating a competitive market. However, Buterin argues that a competitive market alone isn’t sufficient to prevent centralization. A small number of dominant builders could potentially censor transactions or inflate costs.
One key proposal, dubbed FOCIL (Fast Open Committee Inclusion List), would introduce a mechanism to prevent censorship. Under FOCIL, a randomly selected committee would determine a minimum set of transactions that *must* be included in each block. Failure to include these transactions would render the block invalid. This, Buterin suggests, would act as a safeguard against a single builder excluding specific users or transactions, even if that builder controlled the majority of the market.
Buterin also addressed the issue of “toxic MEV” – Maximal Extractable Value – where traders exploit their knowledge of pending transactions to profit by front-running or manipulating trades. A potential solution, he proposed, is to encrypt transactions until they are finalized, shielding them from opportunistic actors. He further suggested exploring anonymized routing systems at the networking layer to prevent intermediaries from observing transactions before they reach a block.
Looking further ahead, Buterin envisions a more distributed block-building process, where not all transactions require global coordination. He argues that much of Ethereum’s activity doesn’t necessitate a single, rigidly ordered block, opening the possibility for designs that reduce central points of control. This aligns with a broader focus on increasing scalability, improving user experience, and enhancing security, as outlined in Ethereum’s 2025 “predictable engineering delivery model,” which informs the Glamsterdam upgrade.
The Glamsterdam upgrade, as detailed in Ethereum Improvement Proposals (EIPs), aims to increase network efficiency and transaction processing speed. It will move block building directly onto the Ethereum network, rather than relying on external relays, thereby increasing decentralization. The upgrade is also expected to reduce gas fees for both simple and complex smart contracts by 78.6% and lower the bandwidth requirements for running nodes, according to recent reports. Developers will also be incentivized to write more efficient code.
Buterin’s roadmap reflects a renewed focus on scaling the base layer of Ethereum, after a period where much of the ecosystem’s scaling strategy centered on layer-2 rollups. The proposals aim to address emerging challenges as Ethereum scales, shifting the focus from validator-level decentralization to the infrastructure that determines which transactions are included on the blockchain.
