Polymarket Snaps Up Prediction Market API Startup Dome

Polymarket has acquired Dome, a Y Combinator-backed startup that built a unified API layer for prediction markets, in the company's second-known acquisition. The move is the latest in Polymarket's push to aggressively expand its developer ecosystem.

What's the Scoop?

• The Context: Dome, a Fall 2025 YC cohort graduate, built infrastructure that lets developers plug into multiple prediction markets, like Polymarket and Kalshi, through a single API.
• The Deal: Polymarket's acquisition price wasn't disclosed, though Dome had previously raised $5.2M across a YC grant and seed round.
• Founder Pedigree: Dome's two co-founders both served as founding engineers at Alchemy, a leading Ethereum infrastructure provider. This background in developer tooling likely made the startup attractive to Polymarket as it looks to deepen its infra.
• Acquisition Streak: The Dome deal marks Polymarket's second acquisition, following its purchase of CFTC-licensed derivatives exchange QCEX, which paved the way for its return to the U.S. market.

Bankless Take:

Polymarket isn't thinking in "single app" terms, as the Dome buyup suggests it's building toward becoming an infra layer that the entire predictions industry can run on. This stronger grip on developer tooling should help consolidate more of the ecosystem's activity around Polymarket's rails over time.