Polymarket has hired former Zora CEO Jacob Horne to lead a product push centered on its DeFi offering, CEO Shayne Coplan confirmed this week.

The announcement lands against a hard internal verdict: the platform's central limit order book cannot be patched into its next phase of growth. On Aug. 31, Josh Stevens, Polymarket's vice president of DeFi engineering, posted that the existing CLOB is "full of tech debt" and that the engineering team had reached a definitive conclusion about its future.

"I think what I want to communicate is that the conclusion now is that the codebase can't be saved long-term," Stevens wrote.

Stevens added that Polymarket had scaled the CLOB roughly tenfold and made it three times faster during prior optimization work, but the foundations remained flawed. The codebase had been patched repeatedly as volumes grew, he said, and each round of optimization exposed new structural weaknesses. Attempts to repair one problem could surface another.

Why is the CLOB under pressure?

Polymarket's documentation describes the CLOB as the layer connecting signed orders from users with settlement on Polygon. Users sign and submit orders to the order book, the exchange operator can match them, and matched trades settle on the Polygon network. The CLOB sits at the core of every onchain market Polymarket operates.

Fees originate in the same layer. Polymarket's current documentation says the venue charges category-based taker fees on certain markets, while makers pay no fees, with collected fees financing rebate programs. Coplan's announcement on Horne did not commit to changes in that structure, and introduced no new liquidity program.

What does the Rust rebuild target?

Stevens said Polymarket is rewriting the matching engine from scratch in Rust. The target launch window is mid-to-late fourth quarter. Stevens reported early benchmark figures:

• 10 to 20 times faster p99 (99th-percentile) latency than the current system
• Capacity of 200,000 orders per second, roughly 15 times current capacity
• Settlement retained on Polygon

The replacement had not launched at the time Stevens published the figures. Stevens said the team would continue maintaining and improving the existing CLOB while building the replacement alongside it, with breaking changes for integrators kept minimal and communicated in advance.

What is Horne's mandate?

Horne joins Polymarket with a broad product mandate rather than a defined engineering role. He most recently served as CEO of Zora, the onchain media and minting protocol. His remit at Polymarket spans the DeFi product surface, with the Rust rewrite already in flight.

The hire layers a senior product figure onto an infrastructure repair already underway, with Stevens continuing as the public voice of the engineering rebuild.

Coplan acknowledged that the performance of Polymarket's onchain product has "waned" while the company scaled. He said some longtime users believed Polymarket had shifted its focus to its U.S. business, and that the company is now working to unify its products. Coplan did not specify a launch date for any unified release and identified no fee, liquidity or routing changes.

When does Polymarket engage users?

Polymarket will hold a DeFi town hall "soon" to collect feedback and outline its plan, Coplan said. He invited users to send feedback directly to Horne or to him in the interim.

The town hall is the next scheduled touchpoint. The mid-to-late Q4 target for the Rust-built matching engine, with reported capacity of 200,000 orders per second on Polygon, is the next hard delivery deadline in the rebuild.