Paradigm-backed Harmonic Launches HFT-Style Block Building to Improve Solana Validator Performance

(PRESS RELEASE – New York, New York, November 5, 2025)

Paradigm is leading a $6 million seed round for a new aggregation layer – introducing exchange-level coordination and open competition between block builders, unlocking greater speed, efficiency and transparency in Solana’s $72 billion validator economy.

Harmonic today announced the launch of Solana’s first open block infrastructure and building builder marketplace, a new aggregation layer that allows validators to source blocks from multiple competing builders. For the first time on Solana, block construction becomes decentralized, transparent and driven by the validator. Alongside the launch of Harmonic, the team also announced its $6 million seed round, led by Paradigm.

In Solana’s existing architecture, each validator takes turns as leader, building and proposing blocks during their assigned slot. While efficient, this design concentrates block-level control in a single operator at a time, prioritizing weighted stakes over performance. Harmonic replaces this bottleneck with a coordinated aggregation layer that routes builder proposals to validators in real time, introducing structured block propagation similar to a high-frequency trading order router.

“Block building shouldn’t be a black box,” said Ben Coverston, co-founder of Harmonic. “Validators should decide what goes into a block, not a single operator or off-chain relayer. Harmonic restores choice, competition and transparency to block production on Solana. In doing so, we aim to bring Solana closer to the deterministic reliability of financial exchange engines such as Nasdaq’s OUCH and INET systems, which are designed for speed, continuous operation and no downtime.”

Thanks to its aggregation layer, Harmonic constantly collects block proposals from independent builders and presents them to validators in real time. Validators can adopt custom policies to guide block selection, including:

• MEV optimization: Maximize returns on arbitration or priority fees.
• Content rules: Apply inclusion or exclusion lists for specific transactions or protocols.
• Policy alignment: Prioritize fairness, compliance, or ecosystem preferences.

“Solana already leads the industry in raw performance, processing thousands of transactions per second with sub-second finality,” said Jakob Povšič, co-founder of Harmonic. “By introducing open competition to block building, we push this advantage even further toward the precision, consistency, and throughput of a global trading engine.”

By opening block construction to multiple builders, Harmonic ensures that value discovery remains competitive and that validators retain full sovereignty over their block decisions. Parallel block sourcing opens new performance ceilings for Solana, which represents one of the largest and fastest-growing validator economies in crypto, with over $72 billion in active participation across approximately 1,000 validators.

“Harmonic’s open aggregation model transforms Solana’s block production into a continuously optimized and competitive marketplace,” said Frankie, investment and research partner at Paradigm. “The result is stock market-grade performance capable of approaching Nasdaq speed in reliability and throughput.