What Is Cross-Platform Matching?
Different prediction market platforms often list markets on the same real-world events. Predexon’s matching system identifies equivalent markets across Polymarket and Kalshi, enabling you to compare prices, find arbitrage opportunities, and analyze cross-platform sentiment.How It Works
Predexon uses LLM-based technology to analyze market titles, descriptions, and resolution criteria across platforms. Each match receives a similarity score indicating how closely the markets align.Match Types
| Type | Similarity Score | Description |
|---|---|---|
| Exact Match | ≥ 95 | Same underlying event with equivalent resolution criteria |
| Related Match | 80–94 | Similar or correlated events, but not identical |
Similarity Score Spectrum
- 98–100: High confidence, virtually identical markets
- 96–97: Confident, strong matches with minor wording variations
- 95–96: Threshold, meets exact match criteria but may have edge cases in resolution
Endpoints
There are two matching endpoints:Find Matches
GET /v2/matching-markets - Given a market identifier from one platform, find its equivalent on the other platform. Returns both exact and related matches with similarity scores.
Matched Pairs
GET /v2/matching-markets/pairs - Get all active exact-matched pairs (similarity ≥ 95) across Polymarket and Kalshi. Useful for scanning all current cross-platform opportunities at once.
Both endpoints return expiration timestamps for each platform, allowing you to filter by when markets expire:
earliest_expiration_ts- the soonest expiration across both platforms- Platform-specific filters:
pm_expires_before,k_expires_before, etc.
The
similarity field may be null for matches created before January 4th, 2025.Use Cases
- Arbitrage detection - compare prices on the same event across Polymarket and Kalshi to find mispricings
- Cross-platform analysis - see how different trader populations price the same event
- Risk management - monitor your exposure to the same event across multiple platforms
Requirements
Cross-platform matching requires a Dev plan or higher. Free tier users will receive a403 error. See Rate Limits & Plans for details.