Over the past two years, Ethereum’s block-building ecosystem has undergone significant centralization. Data shows that more than 80% of Ethereum blocks are currently produced by just a handful of builders, with block-building power increasingly concentrated among advanced participants who can maximize value extraction through optimized transaction ordering. This centralization trend is driven by MEV (Maximal Extractable Value) economics—builders leverage complex ordering algorithms to earn outsized profits, creating natural barriers to entry and specialization. Meanwhile, although the proposer-builder separation (PBS) mechanism aims to prevent centralization at the staking layer, it has inadvertently introduced new centralization risks at the block-building layer. Vitalik Buterin has made it clear that while ePBS can prevent block-building rights from consolidating in a few staking pools, the act of block building itself can still become concentrated among a small group of specialized, MEV-optimized builders.
The core issue arising from this structural shift is the heightened risk of censorship. When a small number of builders control the vast majority of block production, whether or not a transaction gets included in a block is no longer simply the result of an open market, but can instead be subject to the discretion of those builders. For DeFi protocols, stablecoin issuers, and Layer 2 networks that rely on Ethereum as a neutral settlement layer, this uncertainty directly challenges Ethereum’s foundational promise as a credibly neutral platform.
How Does FOCIL Address Transaction Censorship at the Protocol Layer?
FOCIL (Fork-Choice Enforced Inclusion Lists, or EIP-7805) introduces a sophisticated protocol-level mechanism that shifts the authority to mandate transaction inclusion from block builders to a decentralized committee of validators. The core process unfolds in three steps: for each Ethereum slot, the system randomly selects 16 validators to form a temporary committee; each committee member independently observes their local mempool and publishes a local inclusion list of valid transactions they believe should be included in the block; the block proposer aggregates all these lists to construct a candidate block, and validators refuse to vote for any block that omits valid transactions from the committee lists.
The key innovation here is encoding censorship resistance directly into the fork-choice rule. If a block ignores valid transactions from the committee lists—even if those transactions originate from sanctioned addresses—the network will fork away from that block, effectively excluding it from the canonical chain. Compared to previous inclusion list proposals, the random committee mechanism significantly reduces the risks of bribery and extortion, since attackers cannot predict which validators will be selected and would find it extremely difficult to bribe all 16 randomly chosen committee members simultaneously.
Another notable feature of FOCIL is its native support for privacy-focused ecosystems. The committee mechanism is inherently compatible with account abstraction and privacy protocols—users can send transactions via smart accounts, and privacy protocol users do not need to worry about their transactions being identified or censored. This paves the way for Ethereum to evolve toward a more "cypherpunk" ethos.
What Are the Trade-offs of Protocol-Level Censorship Resistance?
Encoding censorship resistance into the consensus layer is not without cost. The primary criticism facing FOCIL centers on legal risk. Detractors argue that forcing validators to include all valid transactions—including those from OFAC-sanctioned addresses—could expose validators operating in the US to regulatory sanctions. Ameen Soleimani, founder of Privacy Pools, noted that after Tornado Cash was sanctioned, about 90% of validators chose not to include transactions related to that privacy protocol. If those validators are compelled to include such transactions, it could lead to direct regulatory conflicts.
From a protocol complexity standpoint, FOCIL requires random committee selection, inclusion list generation, aggregation, and voting validation for every slot—inevitably increasing computational load at the consensus layer. Developers are working to optimize proof sizes and gas efficiency to support future "GigaGas" scalability. Notably, FOCIL was previously excluded from the Glamsterdam upgrade, in part due to concerns within the development community about its complexity and potential latency risks.
In terms of prioritization, Ethereum core developers voted in March 2026 to make FOCIL the sole "headline" feature of the Hegota upgrade, lowering the priority of the framework transactions proposal supported by Vitalik Buterin. Client developers noted that adding a second headline feature could delay Hegota, and the complexity of framework transactions made it difficult to commit to a fixed delivery timeline. This decision clearly reflects the Ethereum development community’s value hierarchy: censorship resistance now takes precedence over user experience improvements.
What Does This Upgrade Mean for the Ethereum Ecosystem?
FOCIL’s implementation will reshape Ethereum’s ecosystem across several dimensions. Economically, it changes the logic of MEV value distribution. Previously, block builders captured MEV by selectively including and ordering transactions; FOCIL forces builders to include committee-listed transactions, limiting their ability to exclude transactions from the mempool and thus weakening their bargaining power. This shift may drive the MEV ecosystem toward greater decentralization.
From a trust model perspective, FOCIL moves Ethereum’s censorship resistance from the realm of social consensus to the protocol rule layer. Previously, Ethereum relied on validator ethics and community oversight—a soft constraint. FOCIL transforms this into a hard, technical requirement embedded in the fork-choice rule, making it impossible for any validator to evade. This significantly strengthens Ethereum’s credibility as the "most neutral blockspace."
Competitively, FOCIL’s launch will further differentiate Ethereum in terms of censorship resistance. While competing networks may focus on higher throughput or lower fees, Ethereum is building an unassailable moat of neutrality through protocol design. Layer 2 developer Tim Clancy has called FOCIL "the most important proposal for Ethereum," as it delivers the core capability Ethereum needs to fulfill its mission.
Where Does FOCIL Fit in Ethereum’s 2026 Roadmap?
The Ethereum Foundation’s 2026 protocol roadmap identifies three main tracks: "scaling," "improving user experience," and "strengthening L1." FOCIL falls under the "strengthening L1" track, alongside post-quantum cryptography research, with a focus on security and censorship resistance. Ethereum has two named upgrades planned for 2026: the Glamsterdam upgrade in the first half, introducing ePBS (built-in proposer-builder separation) and block-level access lists; and the Hegota upgrade in the second half, with FOCIL as its core feature.
Developers have confirmed FOCIL as the "headline" feature for Hegota, and most Ethereum clients have already completed prototype implementations. At the March 26 core developer meeting, the community rejected the proposal to make framework transactions a second headline feature, relegating it to "considered for inclusion" status. This decision ensures FOCIL’s delivery timeline won’t be delayed by other complex proposals, but it also means account abstraction and user experience improvements will take a back seat to censorship resistance in the short term.
Looking ahead, the community is already exploring enhanced versions of FOCIL, such as EIP-8046 (FOCILR, which adds transaction ordering to FOCIL), to provide even stronger censorship resistance by preventing builders from bypassing propagated inclusion lists when blocks are full. There’s also widespread discussion about the synergy between FOCIL and framework transactions—Vitalik Buterin believes FOCIL will work hand-in-hand with framework transactions to drive broader adoption of privacy protocols.
What Are the Potential Risks and Limitations of FOCIL Implementation?
Despite FOCIL’s robust technical guarantees for censorship resistance, its rollout faces several risks and limitations. Regulatory risk is the most immediate external challenge. By forcing validators to include all valid transactions, FOCIL could require US-based validators to process transactions from sanctioned addresses, exposing them to legal consequences. This risk may prompt some validators to exit the Ethereum network or push staking services to relocate to more permissive jurisdictions, potentially increasing geographic centralization among validators.
Greater protocol complexity can also introduce unforeseen vulnerabilities. FOCIL involves random committee selection, list generation and validation, and changes to fork-choice rules—any design flaw in these new components could be exploited by attackers. For example, committee members could submit dishonest inclusion lists, or attackers could attempt to manipulate committee selection. Although the random selection mechanism is designed to resist manipulation, its real-world security will only be proven over time.
From an economic incentives perspective, FOCIL’s impact on the MEV ecosystem is uncertain. On one hand, it limits builders’ ability to selectively exclude transactions; on the other, it may create new MEV extraction methods—such as manipulating the order of transactions within inclusion lists. EIP-8046 was proposed to address this, but any economic mechanism will require iterative refinement in practice.
Additionally, FOCIL cannot solve all forms of censorship. It guarantees that transactions are included in blocks, but does not ensure timely processing or fair ordering. Builders can still influence user experience through gas pricing strategies or transaction ordering. Censorship resistance is a multi-layered engineering challenge—FOCIL addresses the foundational question of "whether transactions are included," but "how they are included" will require further upgrades.
Conclusion
The confirmation of Ethereum FOCIL (EIP-7805) marks a paradigm shift in blockchain censorship resistance design. It elevates censorship resistance from a soft social consensus to a hard protocol rule, transferring transaction inclusion rights from a handful of block builders to a decentralized network of validators via a random committee mechanism. While this upgrade cements Ethereum’s position as the most neutral blockspace, it also introduces new challenges around validator legal risk, protocol complexity, and MEV ecosystem restructuring. As the centerpiece of the Hegota upgrade in the second half of 2026, FOCIL will give Ethereum a structural advantage in censorship resistance that is difficult to replicate. However, its long-term impact will depend on regulatory developments, community consensus, and the effectiveness of future risk mitigation strategies.
FAQ
What does FOCIL stand for? How is it related to EIP-7805?
FOCIL stands for Fork-Choice Enforced Inclusion Lists, which is Ethereum Improvement Proposal EIP-7805. Both refer to the same censorship-resistance mechanism: FOCIL is the common name, while EIP-7805 is its official designation in the Ethereum improvement proposal system.
How is FOCIL different from ePBS?
ePBS (in-protocol proposer-builder separation) is designed to prevent block proposing rights from concentrating in a few staking pools, reducing centralization risks at the staking layer by outsourcing block building to an open market. FOCIL, on the other hand, focuses on preventing block builders from censoring transactions by using validator committees and mandatory inclusion lists to ensure all valid transactions are eventually included in blocks. They address centralization at different layers and are both part of Ethereum’s "strengthening L1" roadmap for 2026.
Will FOCIL delay Ethereum’s upgrade schedule?
Developers have confirmed FOCIL as the sole headline feature of the Hegota upgrade, deprioritizing the framework transactions proposal to prevent upgrade delays due to feature overload. Most clients have already completed prototype implementations, and development is progressing as planned.
Will FOCIL affect the transaction experience for regular users?
For most users, FOCIL’s direct impact is positive—there’s no need to trust any single builder, and the likelihood of transaction censorship drops significantly. However, the additional computation required by FOCIL may introduce some efficiency trade-offs in gas costs and block processing times, depending on network load after launch.
Does FOCIL require all validators to participate?
FOCIL randomly selects 16 validators per slot to form a temporary committee; not all validators need to generate inclusion lists for every slot. This design maintains decentralization while managing computational overhead for each validator. The core responsibility for validators is to refuse to vote for blocks that ignore valid committee-listed transactions, rather than to proactively generate lists every time.
