Polymarket-Kalshi Cross-Platform Arbitrage (BTC/SOL 15-Minute Markets)

How It Works This strategy targets 15-minute BTC and SOL price prediction markets that exist on both Polymarket and Kalshi. Because both platforms independently set prices based on their own liquidity and order flow, temporary price divergences arise where the same binary outcome (e.g., 'BTC above X at 15-min close') trades at different implied probabilities on each platform.

Entry/Exit Conditions The bot continuously monitors both platforms' order books in real time. When the combined cost of buying YES on one platform and NO on the other sums to less than $1.00 (accounting for fees), a risk-free arbitrage position is opened simultaneously on both sides. Positions resolve automatically at contract expiry (15-minute intervals), so no active exit logic is needed beyond expiry.

Verified Results No independently verified P&L results are published in the repository metadata. The Rust-based implementation (kmjjjj) suggests performance optimization is a priority, implying latency sensitivity. Multiple independent implementations of this same strategy exist (haoo99, kmjjjj, Crayz916, samuel483, lufegaga, tduic), indicating the opportunity is widely known and likely competitive.

Implementation Notes Implementations exist in Rust (for speed) and Python (asyncio for concurrency). Key technical requirements include: simultaneous API connections to both platforms, sub-second order routing, fee-aware opportunity filtering, and USDC liquidity management across two platforms. Kelly sizing is mentioned in at least one implementation (tduic) for position sizing proportional to edge size.

Risks Execution risk is the primary concern — if one leg fills and the other does not, a directional position is left open. Fee structures on either platform can erode or eliminate apparent edge. Regulatory changes to either platform's market offerings could eliminate opportunity. High competition from multiple known bots likely compresses available spread.