As Ethereum matures into a settlement layer securing trillions of dollars in value, the need for hard, protocol-level guarantees rather than social or off-chain solutions has never been more critical.
Why Ethereum Needs FOCIL Now
Ethereum’s post-Merge architecture introduced a separation between block proposers (validators) and block builders, a system designed to optimize efficiency and reduce MEV exploitation. While successful in many respects, this structure has also created a new bottleneck.
Recent network data shows that over 85% of Ethereum blocks are built by fewer than five builder entities, with the top two often controlling more than 60% of block production during peak periods. This concentration increases the risk of transaction censorship, delayed inclusion, and preferential ordering especially under regulatory or economic pressure.
FOCIL is designed to rebalance that power by shifting transaction inclusion guarantees back into the consensus mechanism itself.
What FOCIL Does at the Protocol Level
FOCIL, short for Fork-Choice Enforced Inclusion Lists, modifies Ethereum’s fork-choice rule so validators collectively enforce the inclusion of valid transactions. Instead of relying solely on builders to decide which transactions make it into a block, validators can publish inclusion lists derived from the public mempool.
If a proposed block omits transactions that should have been included, validators are allowed by protocol rules to favor alternative forks that respect those inclusion lists.
In practical terms, this creates a time-bounded inclusion guarantee, ensuring that valid transactions cannot be indefinitely ignored, even by dominant builders.
Builder Centralization by the Numbers
The urgency behind FOCIL becomes clear when looking at the data:
90%+ of Ethereum blocks are currently produced using MEV-optimized builders
Top 3 builders regularly account for more than 70% of block share
During high-volatility events, average transaction inclusion times can spike by 2–3× for non-MEV transactions
Censorship-related filtering has previously impacted thousands of transactions per day during periods of regulatory uncertainty
While Ethereum has remained largely functional, these metrics highlight structural fragility rather than outright failure exactly the kind of risk protocol designers aim to eliminate early.
How FOCIL Improves Censorship Resistance
FOCIL introduces protocol-enforced neutrality, removing discretion from centralized actors and embedding fairness directly into consensus logic. Unlike relay-based or opt-in solutions, FOCIL cannot be bypassed without violating fork-choice rules.
Key benefits include:
Reduced reliance on trusted builders
Predictable transaction inclusion windows
Stronger resistance to regulatory capture
Improved reliability for DeFi, rollups, and cross-chain bridges
Analytically, researchers estimate that FOCIL could reduce effective censorship power of dominant builders by over 80%, even without increasing validator overhead significantly.
Performance and Scalability Considerations
One concern raised early in discussions was whether inclusion lists would increase network load or slow down block propagation. Current simulations suggest otherwise.
Early benchmarks indicate:
Less than 3% increase in fork-choice computation overhead
No measurable impact on average block times
Minimal added bandwidth compared to existing consensus messages
This makes FOCIL one of the rare proposals that improves decentralization without trading off scalability.
What This Means for Ethereum’s Future
If finalized and shipped with the Hegota upgrade, FOCIL would mark a defining moment in Ethereum’s evolution cementing censorship resistance not as a social norm, but as an enforceable rule.
For developers, it means stronger guarantees that apps will function as intended. For users, it means confidence that transactions won’t be silently filtered. And for Ethereum itself, it reinforces its position as the most resilient, neutral, and decentralized smart-contract platform at scale.
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