Polymarket US has begun processing multi-leg sports contracts via an API-only beta that went live on August 5, marking a quiet test of parlay-style markets that did not appear in the company’s consumer app. The move comes as rival exchange Kalshi is reported to be applying maker fees to its own parlay product, a change not reflected in its published fee schedule.
API-Only Parlay Beta at Polymarket US
The beta enables select API users to create and trade multi-leg sports contracts, commonly known as parlays—combined wagers that link multiple outcomes into a single position. By limiting access to API users and keeping the feature out of the consumer interface, Polymarket US appears to be testing order flow and liquidity dynamics before a broader release.
Polymarket is a crypto-native prediction market platform known for event-based markets across politics, sports, and current events. The new functionality, if expanded, would broaden its sports coverage and introduce more complex position structures for U.S.-facing users.
Reports of Maker Fees on Kalshi Parlays
Kalshi, a CFTC-regulated event contracts exchange, is reported to be extending maker fees to its parlay product. Maker fees typically apply to limit orders that add liquidity to an order book, while taker fees apply to marketable orders that remove liquidity.
As of publication, Kalshi’s posted fee schedule did not list maker fees for parlays. Any discrepancy between applied and disclosed fees matters for traders who rely on published schedules to model costs and expected returns. Kalshi has not publicly updated its documentation to reflect the reported change.
Why Parlay Structures and Fees Matter
Parlays can increase potential returns by combining multiple outcomes, but they compound risk and introduce additional pricing complexity. Clear and consistent fee schedules are critical to market participants, particularly liquidity providers and algorithmic traders who must account for costs when quoting spreads and managing inventory.
The parallel developments underscore intensifying competition among U.S.-facing prediction platforms to expand sports offerings and differentiate on product features and pricing. Further updates on availability, fee structures, and disclosures will help clarify how each platform positions its parlay markets for retail and professional participants alike.