Prediction Markets API

Real-time prediction market odds and probabilities from Polymarket and Kalshi. Browse active markets, get detailed odds on specific events, and discover trending bets -- all via x402 micropayments. Merges data from both platforms so agents get the most complete view of market sentiment.

What It Does / Endpoints

Endpoint	Price	Description
`POST /api/markets`	$0.005	List active prediction markets with odds, volume, categories from both Polymarket and Kalshi
`POST /api/odds`	$0.005	Detailed odds for a specific market (by ID or search query) -- searches both platforms
`POST /api/trending`	$0.003	Top trending markets ranked by volume from both sources

Example Request / Response

List Markets

curl -X POST https://prediction-markets-production.up.railway.app/api/markets \
  -H "Content-Type: application/json" \
  -d '{"category": "politics", "limit": 5, "sort": "volume"}'

{
  "markets": [
    {
      "id": "0x1234...",
      "question": "Will Trump win the 2028 presidential election?",
      "outcomes": ["Yes", "No"],
      "outcomePrices": { "Yes": 0.42, "No": 0.58 },
      "volume": 15420000,
      "volume24h": 234000,
      "liquidity": 890000,
      "endDate": "2028-11-06T00:00:00Z",
      "category": "politics",
      "active": true,
      "source": "polymarket"
    },
    {
      "id": "PRES-2028-DEM",
      "question": "Will a Democrat win the 2028 presidential election?",
      "outcomes": ["Yes", "No"],
      "outcomePrices": { "Yes": 0.55, "No": 0.45 },
      "volume": 8200000,
      "volume24h": 0,
      "liquidity": 0,
      "endDate": "2028-11-06T00:00:00Z",
      "category": "politics",
      "active": true,
      "source": "kalshi"
    }
  ],
  "count": 5,
  "sort": "volume",
  "category": "politics",
  "source": "polymarket+kalshi"
}

Filter by platform:

curl -X POST https://prediction-markets-production.up.railway.app/api/markets \
  -H "Content-Type: application/json" \
  -d '{"source": "kalshi", "limit": 5}'

Get Odds (Search by Query)

curl -X POST https://prediction-markets-production.up.railway.app/api/odds \
  -H "Content-Type: application/json" \
  -d '{"query": "bitcoin 100k"}'

{
  "id": "0xabcd...",
  "question": "Will Bitcoin reach $100k by December 2026?",
  "outcomes": ["Yes", "No"],
  "outcomePrices": { "Yes": 0.65, "No": 0.35 },
  "volume": 8900000,
  "volume24h": 120000,
  "liquidity": 450000,
  "endDate": "2026-12-31T00:00:00Z",
  "category": "crypto",
  "active": true,
  "source": "polymarket",
  "matchedFrom": 3
}

Trending Markets

curl -X POST https://prediction-markets-production.up.railway.app/api/trending \
  -H "Content-Type: application/json" \
  -d '{"limit": 5}'

{
  "trending": [
    {
      "id": "0x5678...",
      "question": "Will the Fed cut rates in July 2026?",
      "probability": 0.73,
      "outcomePrices": { "Yes": 0.73, "No": 0.27 },
      "volume24h": 890000,
      "totalVolume": 12500000,
      "category": "politics",
      "endDate": "2026-07-31T00:00:00Z",
      "active": true,
      "source": "polymarket"
    },
    {
      "id": "FED-RATE-JUL26",
      "question": "Will the Fed cut rates in July 2026?",
      "probability": 0.71,
      "outcomePrices": { "Yes": 0.71, "No": 0.29 },
      "volume24h": 0,
      "totalVolume": 5400000,
      "category": "politics",
      "endDate": "2026-07-31T00:00:00Z",
      "active": true,
      "source": "kalshi"
    }
  ],
  "count": 5,
  "source": "polymarket+kalshi"
}

Use Cases

Election odds: Get real-time probabilities on political outcomes backed by real money from both crypto-native (Polymarket) and CFTC-regulated (Kalshi) platforms
Crypto predictions: Check market consensus on price targets, ETF approvals, protocol upgrades
Event forecasting: Find the crowd-sourced probability of any major world event
Cross-platform comparison: Compare odds between Polymarket and Kalshi for the same events
Research & analysis: Use prediction market data as a signal for decision-making
News impact: See how breaking events shift market probabilities in real time

MCP Integration

Add to your Claude Desktop or Cursor MCP config:

{
  "mcpServers": {
    "prediction-markets": {
      "url": "https://prediction-markets-production.up.railway.app/sse"
    }
  }
}

Tools available via MCP:

prediction_list_markets -- Browse active markets by category, sort, and platform (Polymarket or Kalshi)
prediction_get_market_odds -- Get detailed odds by market ID or search query (searches both platforms)
prediction_trending_markets -- Discover trending markets by volume from both sources

Payment

All endpoints are gated by x402 micropayments (USDC on Base L2). Agents pay automatically per call -- no API keys, no subscriptions.

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