What Harmonic and open block building are

In this episode of Talking Tokens, Jacquelyn Melinek speaks with Ben Coverston, Founding Engineer at Temporal, a Solana-based R&D firm focused on blockchain performance, and cofounder of Harmonic.

The conversation explores Harmonic, a new open block-building system designed to make Solana’s transaction sequencing more efficient, decentralized, and transparent. Ben discusses how the system creates a competitive marketplace for block builders, improves inclusion latency, and could help Solana reach 1 million transactions per second while maintaining decentralization.

They also talk about the lessons he learned from Solana’s early struggles, the evolution of validator coordination, and how Harmonic’s work brings the network closer to functioning like an “onchain Nasdaq.”This episode is a part of the Solana Sessions campaign that Token Relations and the Talking Tokens podcast are doing, diving into founders’ journeys and startups building on Solana. Check out the accompanying newsletter on ⁠www.token-relations.xyz⁠This episode is sponsored by Forgd. Thousands of Web3 projects leverage Forgd’s free tools to design smarter tokenomics, engage market makers on fair terms, plan listings strategically, and monitor liquidity after launch. Start using the Forgd platform for free, or sign up for white-glove advisory services, at Forgd.com

Timestamps

(00:00) - Intro: Solana’s progress & how Temporal fits in

(01:03) - Creating an “onchain Nasdaq” for Solana

(02:15) - Ben’s background: from math & CS student to interning at Citadel

(03:19) - What drew him from traditional finance to crypto

(04:11) - First impressions of Solana’s speed and performance

(05:25) - Why Ben left HFT firms to build in decentralized finance

(06:20) - Problems with centralized markets and the appeal of DeFi transparency

(07:04) - How Solana achieved real efficiency and low fees

(08:50) - Understanding more about Harmonic

(10:15) - Why sequencing and inclusion latency matter for DeFi apps

(11:35) - Standardizing Solana’s transaction rules with ACE (Application Controlled Execution)

(13:13) - Why open sequencing helps apps like DEXs and liquidators

(14:04) - Bringing predictability and competition to Solana’s block production

(15:32) - How multiple builders competing improves network throughput

(16:51) - The goal: Solana reaching 10 to 100x throughput with stability

(18:06) - Long-term potential can be 1 million TPS and sustainable decentralization

(19:22) - How open sequencing improves inclusion, latency and efficiency

(20:57) - Building trust between validators, builders, and applications

(22:13) - Preventing toxic block-building practices

(23:46) - Why transparency and fairness increase validator revenue

(25:04) - What “success” looks like for Solana developers and apps

(26:33) - Why Solana’s user and institutional adoption is accelerating

(28:10) - The role of liquidity providers and market competition

(29:12) - Institutional capital, DeFi adoption & network maturity

(31:04) - Advice from Ben: ignore short-term noise, keep building

(32:33) - Closing thoughts & future of open blockchain design

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