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

In this guide

Available Data Endpoints
Python Quickstart
Use Cases
FAQ

Developers seeking to leverage prediction market intelligence for compliance research, regulatory analysis, and quantitative modelling can access comprehensive datasets through the Polymarket infrastructure (via PolyGram). The platform's APIs unlock detailed market signals across the world's most liquid prediction market venue, supporting use cases from legal due diligence to algorithmic trading oversight.

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 trajectories across prediction markets for regulatory event tracking and outcome forecasting
News tools: Identify markets exhibiting rapid movement in response to material information disclosures
Aggregators: Benchmark pricing signals across Polymarket, Kalshi, and Metaculus for consistency and arbitrage detection
Alert systems: Trigger notifications when market movements exceed specified volatility or directional parameters
Academic research: Analyse historical settlement records to evaluate forecast accuracy and market efficiency under various regulatory regimes

FAQ

Is the Polymarket API free to use?: Yes — market data endpoints (Gamma API) are available at no cost subject to standard rate limits (approximately 100 requests per minute for unauthenticated access). CLOB order submission functionality requires account funding; however, data retrieval operations remain complimentary.
Is there a Python library for Polymarket?: Multiple community-developed Python packages are available via GitHub repositories. Searching for "polymarket-py" will surface actively maintained implementations.