November 5, 2025 – New York, New York
Paradigm leads $6 million seed round for new aggregation layer introducing exchange-grade coordination and open competition among block builders, unlocking greater speed, efficiency and transparency across Solana’s $72 billion validator economy
Harmonic announced today the launch of Solana’s first open block building infrastructure and builder market a new aggregation layer that allows validators to source blocks from multiple, competing builders.
For the first time on Solana, block building becomes decentralized, transparent and validator-driven.
In conjunction with 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 a leader, building and proposing blocks during their assigned slot.
While efficient, this design concentrates block-level control in one operator at a time, prioritizing weighted stake over performance.
Harmonic replaces that 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.
Ben Coverston, co-founder of Harmonic, said,
“Block building shouldn’t be a black box. Validators should decide what goes into a block, not a single operator or off-chain relay.
“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 zero downtime.”
Through its aggregation layer, Harmonic continuously collects block proposals from independent builders and presents them to validators in real time.
Validators can adopt custom policies to guide block selection, including the following.
Jakob Povsic, co-founder of Harmonic, said,
“Solana already leads the industry in raw performance, processing thousands of [TPS] (transactions per second) with sub-second finality.
“By introducing open competition in block building, we push that advantage even further toward the precision, consistency and throughput of a global exchange engine.”
By opening block construction to multiple builders, Harmonic ensures that value discovery remains competitive and validators retain full sovereignty over their block decisions.
Parallel block sourcing unlocks new performance ceilings for Solana, which represents one of the largest and fastest-growing validator economies in crypto, with more than $72 billion in active stake across approximately 1,000 validators.
Frankie, investing and research partner at Paradigm, said,
“Harmonic’s open aggregation model transforms Solana’s block production into a continuously optimized and competitive marketplace.
“The result is exchange-grade performance capable of approaching Nasdaq speed in both reliability and throughput.”
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