Gemini introduces Custom Combos RFQ API for beta testing in prediction markets push

Gemini is rolling out a new trading tool that brings Wall Street-style execution mechanics to prediction markets. The exchange’s Custom Combos feature, now live for beta testing in its sandbox environment, lets market makers submit sealed bids on multi-leg prediction market contracts through a Request-for-Quote API. How the system actually works The RFQ process runs on a tight clock. Market makers get a 1-second window to submit their quotes after a request comes in. The requester then has 5 seconds to accept the best bid. Finally, the winning maker gets a 1-second “last-look” confirmation period to finalize the trade. That entire lifecycle runs through a series of defined states: OPEN, PENDING_ACCEPTANCE, CONFIRMING, and FINALIZING. The whole thing wraps up in roughly 7 seconds. The sealed-bid design means competing market makers can’t see each other’s quotes. Only the winning bid gets disclosed after the auction concludes. Contracts require at least two legs, which means traders can construct custom combinations of prediction market positions rather than being limited to single-outcome bets. Production access remains locked down during this controlled beta phase. Developers and m...