Every EEZ Batch Landed in Builder-Made Blocks in First Month

Every Ethereum Economic Zone batch in the system's first month landed in an externally built MEV-Boost block, according to on-chain inclusion records. The result confirms that same-block calls across connected chains function as designed. It also confirms a structural dependence: the roughly 7% of Ethereum blocks that validators build themselves offer no synchronous-call guarantee at all.

The concentration is measurable. Titan-built blocks carried 56% of EEZ batches in the period, against Titan's usual 48% share of overall Ethereum block production. In plain terms, EEZ traffic over-indexed to one builder by about eight percentage points. That gap suggests builders with composer integration capture disproportionate EEZ flow; whether that entrenches Titan's position over time is a question the first month cannot answer.

What is an EEZ, mechanically?

EEZ is a set of Ethereum contracts and participation rules that connects chains without creating a new chain or software stack. A connected rollup can call contracts and use liquidity on Ethereum mainnet, or on another participating chain, within the same block. Each chain retains control of its own virtual machine, transaction ordering and admission rules.

Admission carries hard constraints. To join, a chain must prove its updated state within one Ethereum slot — 12 seconds — and roll back whenever Ethereum reorganizes. The rollback requirement prevents a chain from retaining state based on a discarded version of Ethereum's history.

Cross-chain calls rely on proxy addresses calculated with CREATE2 from three inputs: the EEZ contract address, the original contract address and the chain ID. Before block assembly, a composer simulates the proposed transaction across every involved chain. An execution table records each call's answer, rollup state roots from before and after the calls, callbacks to Ethereum and a rolling hash.

The bundle is all-or-nothing. A proof covers the table, and the builder must include the complete bundle or omit it entirely. If actual Ethereum execution diverges from the simulation, operations revert on both Ethereum and the rollup. Atomicity holds, in other words, at the cost of strict dependence on the builder pipeline.

What are the trade-offs?

The design forces a choice. A connected chain cannot simultaneously have fast block times, synchronous calls to Ethereum and decentralized sequencing; it must pick two. That trilemma is stated plainly in the system's own architecture, and adopters should read it as a promise with a price attached.

There is also a visibility problem. The composer must see unencrypted transactions before assembly, which grants both the composer and the builder visibility into potential MEV. Every efficiency gain in same-block execution therefore arrives with privileged pre-assembly access for a small set of operators — a caveat worth weighing against the interoperability gains.

Onboarding adds one more gate. A chain's onboarding rules must specify which proof systems it accepts, which constrains the set of chains that can participate before any technical integration begins.

The first-month record shows the mechanism works when external builders produce the block. The unresolved question is the 7% of slots where they do not, and whether EEZ can extend synchronous guarantees into validator-built blocks before builder concentration hardens into a single point of dependence.

By Elena Vasquez