PolyHistorical vs Polygon.io for Market Data APIs
How PolyHistorical compares to Polygon.io for market data APIs — prediction markets vs equities and crypto.
Overview
Polygon.io is a popular market data API covering US stocks, options, forex, and crypto. PolyHistorical specializes in Polymarket prediction market order book data. Despite similar-sounding names, these are very different products serving different data needs.
Feature Comparison
| Feature | PolyHistorical | Polygon.io |
|---|---|---|
| Prediction Markets | ✓ Full order book history | ✗ Not covered |
| US Stocks | ✗ | ✓ All US exchanges |
| Crypto Data | Polymarket only | ✓ Major exchanges |
| Options Data | ✗ | ✓ Full US options chain |
| Order Book Depth | ✓ Sub-second snapshots | ✓ NBBO + depth (equities) |
| Free Tier | ✓ BTC markets included | ✓ Delayed data, limited calls |
| Starter Pricing | $11/month | $29/month |
API Design Philosophy
Polygon.io follows traditional financial data API conventions — ticker-based queries, OHLCV bars, trade-level data, and reference data for equities. PolyHistorical is designed specifically for prediction market research, with endpoints optimized for order book snapshot retrieval, time-range queries, and market-specific filtering.
Polygon.io Strengths
- Comprehensive US equities and options coverage
- Real-time WebSocket streaming
- Extensive reference data and corporate actions
- Well-established with large developer community
PolyHistorical Strengths
- Only source for Polymarket historical order book data
- Sub-second granularity designed for quantitative research
- Purpose-built for prediction market backtesting
- Affordable pricing with a generous free tier
Cross-Market Research
An interesting use case combines both APIs: use Polygon.io for underlying asset prices (BTC, ETH via their crypto endpoints) and PolyHistorical for the prediction market order books. This lets you analyze how prediction market liquidity and pricing respond to spot market movements — a powerful research angle for quantitative traders.
Who Should Choose Which
Choose Polygon.io if you need stocks, options, forex, or broad crypto exchange data. Choose PolyHistorical if you need Polymarket prediction market order book history for backtesting, market making, or academic research. The two APIs complement each other well for cross-market analysis.