<p>In this episode, host Friederike Ernst is joined by Kubi Mensah, CEO and co-founder of Gattaca, the company behind Titan Builder. Kubi sheds light on the highly competitive and often opaque world of Ethereum block building, explaining how Gattaca evolved from a centralized exchange proprietary trading firm to one of the three dominant builders responsible for constructing the vast majority of Ethereum blocks today .<br> </p><p><br></p><p><br> <br>They dissect the true &quot;journey of a transaction,&quot; revealing why over half of all Ethereum transaction value bypasses the public mempool in favor of private order flow auctions and MEV-protection services . Kubi explains the intricate mechanics of top-of-block bidding by high-frequency DeFi arbitrageurs, the necessity of extreme latency optimization, and the &quot;flywheel effect&quot; that makes block building a natural oligopoly . Finally, the discussion turns to the future of the Ethereum roadmap, unpacking how upcoming upgrades like ePBS (enshrined Proposer-Builder Separation) and FOCIL (Fork-Choice Enforced Inclusion Lists) aim to permanently alter the power dynamics between block builders, validators, and originators .<br> <br> <br>Topics<br></p><p><br></p><ul><li>04:15 Transitioning from TradFi Trading to Ethereum Block Building</li><li>09:30 Redefining the Builder: Relays and Order Flow Auctions</li><li>15:00 Unpacking the Mempool: Public vs. Private Transactions</li><li>21:45 The Anatomy of a Block &amp; &quot;Top-of-Block&quot; Arbitrage</li><li>27:10 How Builders Pay Proposers to Win Auctions</li><li>35:20 The Oligopoly: Why Only 3 Builders Dominate Ethereum</li><li>42:15 Trust in the Dark Forest: Handling Searcher Bundles</li><li>49:00 The Convergence of Builders and Solvers</li><li>55:30 The Impact of ePBS, FOCIL, and Pre-confirmations</li></ul><p><br></p><p><br></p><p><br></p><p>Sponsors: </p><p><br></p><p><br></p><p>Lido V3 introduces stVaults: a modular staking infrastructure that lets builders and institutions deploy custom staking vaults, while staying anchored to stETH as a shared liquidity layer.Get started building with Lido V3 today: https://lido.fi/stvaults?mtm_campaign=epicenterBlock Space Forum: https://blockspace.forum/</p>