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

In this guide

Available Data Endpoints
Python Quickstart
Use Cases
FAQ

Developers, researchers, and analysts increasingly rely on prediction market intelligence for strategic decision-making and quantitative modelling. PolyGram unlocks access to comprehensive APIs built on top of the globe's most liquid prediction market infrastructure, enabling sophisticated data extraction and integration workflows.

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 in real time for targeted events and outcomes
News tools: Identify and highlight markets experiencing significant movement in response to fresh developments
Aggregators: Benchmark implied probabilities across multiple platforms including Polymarket, Kalshi, and Metaculus
Alert systems: Trigger notifications whenever market conditions breach predefined volatility or price boundaries
Academic research: Leverage resolved market outcomes and historical data for empirical studies on forecast performance and market efficiency

FAQ

Is the Polymarket API free to use?: Absolutely — the Gamma API for market data access is offered at no cost, though unauthenticated requests face rate restrictions (approximately 100 calls per minute). Submitting orders via the CLOB requires wallet funding; however, read-only data queries remain complimentary.
Is there a Python library for Polymarket?: Multiple community-developed Python packages are available through GitHub repositories. Look for "polymarket-py" to discover actively maintained implementations.