Using the Polymarket Data API: Real-Time Prediction Market Data for Developers | Polymarket Review UK

In this guide

Available Data Endpoints
Python Quickstart
Use Cases
FAQ

Developers, researchers, and analysts increasingly rely on prediction market signals for quantitative workflows and investigative projects. PolyGram grants programmatic access to Polymarket's comprehensive dataset—the globe's most liquid prediction exchange—through a suite of production-grade APIs.

Available Data Endpoints

Gamma API (Market Data)

GET https://gamma-api.polymarket.com/events
  ?limit=100&active=true&order=volume24hr
  Returns: event metadata, current prices, volume, tags

GET https://gamma-api.polymarket.com/events/{slug}
  Returns: full event with all markets, prices, descriptions

GET https://gamma-api.polymarket.com/markets/{conditionId}
  Returns: single market details, current order book price

CLOB API (Order Book)

GET https://clob.polymarket.com/book
  ?token_id={tokenId}
  Returns: full order book depth (bids/asks)

GET https://clob.polymarket.com/prices/history
  ?market={conditionId}&resolution=1h&startTs=1700000000
  Returns: hourly price history

WebSocket: wss://ws-subscriptions-clob.polymarket.com
  Subscribe to real-time price updates

Python Quickstart

import requests

# Get top prediction markets by volume
r = requests.get(
    "https://gamma-api.polymarket.com/events",
    params={"limit": 10, "active": "true", "order": "volume24hr"}
)
for event in r.json():
    market = event["markets"][0] if event.get("markets") else {}
    prices = market.get("outcomePrices", "[0.5,0.5]")
    import json; p = json.loads(prices)
    print(f"{event['title'][:50]}: YES={float(p[0]):.2%}")

Use Cases

Research dashboards: Monitor probability shifts across time horizons for targeted events and outcomes
News tools: Identify rapidly-moving markets responding to fresh developments
Aggregators: Benchmark Polymarket odds against competing platforms including Kalshi and Metaculus
Alert systems: Trigger notifications once market movement exceeds configured tolerance bands
Academic research: Leverage settled market records to evaluate prediction accuracy and model performance

FAQ

Is the Polymarket API free to use?: Absolutely — querying market data via the Gamma API carries no cost and operates under standard rate limits (approximately 100 requests per minute without authentication). Submitting orders on the CLOB requires wallet funding, though data retrieval remains complimentary.
Is there a Python library for Polymarket?: Community developers maintain several Python packages across GitHub repositories. Look for "polymarket-py" to discover actively-maintained implementations.