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

In this guide

Available Data Endpoints
Python Quickstart
Use Cases
FAQ

Forecasting and market analysis rely increasingly on prediction market signals, which serve researchers, financial journalists, and algorithmic traders alike. PolyGram provides access to Polymarket's comprehensive API suite, enabling developers to leverage the globe's most liquid prediction market infrastructure for custom applications.

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 prediction markets throughout an event's lifecycle
News tools: Identify markets experiencing significant movement in response to current events
Aggregators: Benchmark odds between Polymarket, Kalshi, and Metaculus side by side
Alert systems: Trigger notifications whenever a market breaches predefined volatility or price boundaries
Academic research: Analyse historical settlement records to evaluate prediction accuracy and market efficiency

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 without authentication). Submitting orders via the CLOB requires a wallet with sufficient funds, though data retrieval itself remains complimentary.
Is there a Python library for Polymarket?: Multiple community-built Python packages are available on GitHub. Look for "polymarket-py" to locate the most actively maintained implementations.