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 .

They dissect the true "journey of a transaction," 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 "flywheel effect" 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 .

Topics

04:15 Transitioning from TradFi Trading to Ethereum Block Building
09:30 Redefining the Builder: Relays and Order Flow Auctions
15:00 Unpacking the Mempool: Public vs. Private Transactions
21:45 The Anatomy of a Block & "Top-of-Block" Arbitrage
27:10 How Builders Pay Proposers to Win Auctions
35:20 The Oligopoly: Why Only 3 Builders Dominate Ethereum
42:15 Trust in the Dark Forest: Handling Searcher Bundles
49:00 The Convergence of Builders and Solvers
55:30 The Impact of ePBS, FOCIL, and Pre-confirmations

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