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. Market makers get a 1-second window to submit their quotes after a request comes in. AdvertisementThe sealed-bid design means competing market makers can’t see each other’s quotes. 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. The prediction markets arms raceGemini entered the prediction markets space in late 2025, and Custom Combos represent its bid to differentiate in an increasingly crowded field.