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Prediction Market API Documentation
Use TPM to access Polymarket and Kalshi data, normalize prediction market prices, find cross-platform spreads, and build market-aware products.
Cross-Platform
Discover events and find price gaps across Kalshi and Polymarket.
Signals
Analyze trending markets, news sentiment, and global API stats.
Get a key
Create a developer account and issue an API key.
Real response from production APICross-platform spread example
Find live Kalshi/Polymarket price gaps
This request returns real data captured from production. Prices and spreads change over time.
Request
curl 'https://api.thepredictionmarkets.com/api/v2/spreads/top?limit=5&window=24' \
-H 'X-API-Key: YOUR_TPM_API_KEY'Response200 OK
{
"data": [
{
"event_slug": "top-artist-on-spotify-us-in-2026",
"event_title": "Top Artist on Spotify U.S. in 2026?",
"outcome_title": "Drake",
"platform_a": "polymarket",
"platform_b": "kalshi",
"price_a": 0.1055,
"price_b": 0.79,
"spread_bps": 6845,
"confidence": 0.628,
"is_stale": false,
"updated_at": "2026-04-22T02:30:53.049830",
"platform_a_url": "https://polymarket.com/event/top-spotify-artist-2026",
"platform_b_url": "https://kalshi.com/markets/kxtopartistusa",
"matching_strategy": "normalized_title_fallback",
"match_quality": "auto_medium"
},
{
"event_slug": "which-bills-will-become-law-in-2026-1",
"event_title": "Which bills will become law in 2026?",
"outcome_title": "Credit-card routing competition",
"platform_a": "kalshi",
"platform_b": "polymarket",
"price_a": 0.08,
"price_b": 0.44,
"spread_bps": 3600,
"confidence": 0.628,
"is_stale": false,
"updated_at": "2026-04-22T02:30:53.049830",
"platform_a_url": "https://kalshi.com/markets/kxbills",
"platform_b_url": "https://polymarket.com/event/which-bills-will-become-law-in-2026",
"matching_strategy": "normalized_title_fallback",
"match_quality": "auto_medium"
}
],
"count": 2
}Build with TPM
Get your API key
Start with Kalshi and Polymarket market data, then add unified spreads, signals, alerts, and watchlists as your workflow grows.