Polymarket–Kalshi BTC 15-Minute Market Arbitrage

How It Works Both Kalshi and Polymarket offer binary contracts on whether BTC price will be higher or lower than a reference price over a 15-minute window. Because these contracts have short duration and high turnover, price gaps between platforms can open and close rapidly. The bot monitors both platforms' order books in real time, calculates the implied probability on each, and fires paired orders when a locked arbitrage exists.

Entry / Exit Conditions Entry when: P_polymarket(YES) + P_kalshi(NO) < 1 (or vice versa), net of fees, with sufficient liquidity on both sides. Given the 15-minute settlement cycle, positions are held to expiry rather than actively managed.

Verified Results No empirical results are published. The Juanp2389 repo has zero stars and forks, indicating no community validation.

Implementation Notes Built in TypeScript. The 15-minute contract cycle creates a natural rhythm for the scanner: opportunities must be identified and executed within the settlement window. High-frequency polling of both APIs is required, and latency becomes critical since the contract value can change sharply as BTC moves.

Risks - Extremely short settlement windows mean partial fills leave large residual directional exposure to BTC price. - BTC price volatility during the 15-minute window can make theoretical arbitrage unprofitable if legs fill at different times. - Both platforms' APIs may throttle high-frequency requests. - Regulatory differences between Kalshi (CFTC-regulated) and Polymarket may affect settlement interpretations for borderline price movements.