Endpoints JSON gratuits et sans clé pour les cotes, le volume et les trades de baleines des marchés de prédiction — pour les développeurs et les agents IA.
CoinRithm aggregates prediction markets and forecasting platforms into a single dataset: Polymarket, Kalshi, Metaculus, PredictIt, Limitless, Manifold Markets, Smarkets, Robinhood (Rothera), Futuur, Myriad, and ForecastEx. The five endpoints below expose that dataset as plain JSON — global stats and category breakdowns, a ranked and filterable event list with live probabilities, 24h volume, probability sparklines and cross-venue reference probabilities, single-event detail with cross-source matches, resolution provenance and daily volume history, per-event probability price history, and a global feed of verified large trades with source-specific evidence and latency labels. No API key, no signup — just JSON over HTTPS.
One request, no auth. This example asks for the single highest-volume open market:
curl "https://api.coinrithm.com/api/prediction-markets/events?status=open&sort=volume24h_desc&limit=1"
Response (trimmed, real shape)
{
"data": [
{
"slug": "world-cup-winner",
"title": "World Cup Winner",
"status": "open",
"volume24h": 68633336.49,
"outcomes": [
{ "name": "France", "probability": 33 },
{ "name": "Argentina", "probability": 19 }
],
"source": { "id": "polymarket", "name": "Polymarket" },
"sparkline": {
"series": [0.2, 0.22, 0.24, 0.29, 0.33, 0.35],
"leaderOutcomeId": "108233…483842092",
"capturedAt": "2026-07-03T08:41:49.808Z"
}
}
],
"pagination": { "limit": 1, "offset": 0, "hasMore": true }
}| Method | Path | Params | Response (top-level) |
|---|---|---|---|
| GET | /api/prediction-markets/overview | fiat (optional, default USD) | stats { totalMarkets, totalOpenMarkets, totalClosedMarkets, totalVolume, volume24h, totalLiquidity }, highlights { gainers, losers, expiring }, categories[], bySource[], byCategory[], updatedAt |
| GET | /api/prediction-markets/events | status (open | closed), sort (best | volume24h_desc | priceChange24h_desc | priceChange24h_asc | endDate_desc | trending), source, q, limit (1-100, default 20), offset, fiat | data[] — event objects (outcomes, volume, priceChange24h/7d as absolute probability-point changes, source, a sparkline field on open events once ≥2 probability points exist, and referenceProbability — the cross-venue consensus for the leading outcome — on open events matched across 2+ venues), pagination { limit, offset, hasMore }, meta { sources[] } |
| GET | /api/prediction-markets/events/{source}/{slug} | fiat (optional, default USD) — source is one of the 12 venue ids below | event, relatedEvents[], crossSourceMatches[], resolution, referenceProbability, volumeHistory[] (daily volume/volume24h points, capture began 2026-07-02), relatedNews[], topicRelatedCoins[], agentsTradingMarket, recentWhaleTrades[], translations |
| GET | /api/prediction-markets/whales | none — fixed top 50 trades, most recent first | trades[] — wallet, traderName, side, outcome, marketQuestion, usdValue, price, tradedAt, event { source, slug, title } |
| GET | /api/prediction-markets/event/{source}/{slug}/price-history | interval (1h | 6h | 1d | 1w | 1m | max; default 1w — some markets are sparse at 1w, fall back to 1d or max) | source, slug, interval, points[] — { t (ms epoch), p (leading-outcome probability, 0-1) }; [] when the venue has no history at that interval |
| GET | /api/prediction-markets/stream | none — Server-Sent Events (text/event-stream) | named events every ~15s tick: 'deltas' (top price moves — source, slug, title, priceChange24h, volume24h), 'whale' (new large prints, same shape as /whales), 'resolution' (freshly resolved events); comment heartbeats keep the connection alive, retry hint on connect |
| GET | /api/prediction-markets/calibration | none | three labeled accuracy series over resolved markets: scored[] (per-venue ECE + reliability bins at t-24h before resolution), finalPrice (venue-reported final pre-resolution prices, per-year back to 2016 where verified), ownCapture (our own last pre-resolution captures with published per-venue lead times); each series carries its own methodology string — the bases are NOT cross-comparable |
| GET | /api/prediction-markets/resolved | source (optional venue id), limit (1-100, default 24), offset, fiat | data[] — resolved event objects with winning outcome and resolution provenance, pagination { limit, offset, hasMore }, totalResolved |
| GET | /api/prediction-markets/resolved/summary | source (required venue id) | source, totalResolved, earliestYear, providerTimeShare (0-1), byYear[] — { year, events }; same definitive-resolution filter as /resolved |
This data is free to use, including in production. If you publish numbers, charts, or answers built from it, please attribute CoinRithm and link back:
Data by CoinRithm — https://www.coinrithm.com
Attribution helps readers verify the source, and it helps us keep these endpoints open and keyless.