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Get your free API key at dashboard.predexon.com to unlock higher rate limits and try all endpoints interactively.

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Overview

Predexon API provides RESTful endpoints for accessing prediction market data. All endpoints return JSON responses and use standard HTTP methods.

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Base URL

https://api.predexon.com

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API Versions

All v2 endpoints are under /v2/. If you’re using v1, switch versions using the dropdown at the top of the page.

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Endpoint Categories

Polymarket

Markets, prices, candlesticks, orderbooks, trades, wallet positions, and P&L.

Cross-Platform Matching

Find equivalent markets across Polymarket and Kalshi.
Kalshi endpoints coming soon. Currently, Kalshi data is available through the cross-platform matching API.

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Common Parameters

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Pagination

Most list endpoints support two pagination methods:

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Offset-based Pagination

ParameterTypeDefaultDescription
limitinteger20-100Number of items to return
offsetinteger0Number of items to skip
{
  "pagination": {
    "limit": 20,
    "offset": 0,
    "total": 1234,
    "has_more": true
  }
}

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Key-based Pagination

For large datasets or real-time data, use cursor/key-based pagination for better performance:
ParameterTypeDescription
limitintegerNumber of items to return
cursorstringPagination cursor from previous response
{
  "pagination": {
    "limit": 100,
    "next_cursor": "eyJpZCI6MTIzNDV9",
    "has_more": true
  }
}
Pass next_cursor as the cursor parameter in subsequent requests to fetch the next page.

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Time Parameters

Time-based endpoints accept Unix timestamps in seconds:
ParameterTypeDescription
start_timeintegerStart of time range (Unix timestamp)
end_timeintegerEnd of time range (Unix timestamp)
Some endpoints (like orderbooks) use milliseconds. Check individual endpoint documentation.

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Sorting

Endpoints with sortable results accept:
ParameterTypeDescription
sortstringField to sort by
orderstringasc or desc

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Response Format

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Success Responses

All successful responses return HTTP 200 with JSON body: 
{
  "markets": [...],
  "pagination": {...}
}

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Error Responses

Errors return appropriate HTTP status codes with a JSON body: 
{
  "error": "Invalid filter combination",
  "message": "Only one of market_slug, token_id, or condition_id can be provided"
}
Status CodeDescription
400Bad Request - Invalid parameters
403Forbidden - Invalid or missing API key
404Not Found - Resource doesn’t exist
429Too Many Requests - Rate limit exceeded
500Internal Server Error
503Service Unavailable - Database issue

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Health Check

Verify API availability: 
curl https://api.predexon.com/health

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OpenAPI Specification

The complete OpenAPI 3.0 specification is available for generating client SDKs:

OpenAPI Specification

Download the OpenAPI JSON specification

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Global Constraints

The following constraints apply across all v2 endpoints:
ConstraintValue
Max search length100 characters (minimum 3)
Max array filter items50 items
Offset has no upper limit. Individual endpoint limits vary—see each endpoint for specific limit ranges.

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Rate Limits

TierRate LimitMonthly RequestsOveragePrice
Free1 req/sec1,000—$0/month
Dev20 req/sec1,000,000$5 / 100K$49/month
Pro100 req/sec5,000,000$2.50 / 100K$249/month
EnterpriseCustomUnlimited—$499+/month

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Free Endpoints (All Plans)

The following endpoints are free and unlimited — they do not count toward your monthly usage limits on any plan: Polymarket:
  • /v2/polymarket/markets — List markets
  • /v2/polymarket/events — List events
  • /v2/polymarket/crypto-updown — Crypto up/down markets
  • /v2/polymarket/market-price/{token_id} — Market price
  • /v2/polymarket/candlesticks/{condition_id} — Candlesticks
  • /v2/polymarket/volume-chart/{condition_id} — Volume chart
  • /v2/polymarket/orderbooks — Orderbook history
  • /v2/polymarket/trades — Trades history
  • /v2/polymarket/activity — Wallet activity
  • /v2/polymarket/markets/{token_id}/volume — Volume time series
  • /v2/polymarket/markets/{condition_id}/open_interest — Open interest
  • /v2/polymarket/positions — All positions
Kalshi:
  • /v2/kalshi/markets — List markets
  • /v2/kalshi/trades — Trades history
  • /v2/kalshi/orderbooks — Orderbook history
Dflow:
  • /v2/dflow/trades — Trades history

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Gated Endpoints (Dev & Pro only)

The following endpoint categories require a Dev or Pro tier subscription:
  • Cross-Platform Matching — /v2/matching-markets/*
  • Smart Money & Analytics — Leaderboards, cohort stats, wallet profiles, smart activity
  • Binance Data — /v2/binance/*
Free tier users will receive a 403 error when accessing these endpoints. See predexon.com/pricing for full plan comparison. Implement exponential backoff when you receive 429 responses.