Using the Polymarket Data API: Real-Time Prediction Market Data for Developers | Oscar Predictions 2026

In this guide

Available Data Endpoints
Python Quickstart
Use Cases
FAQ

Forecasting and data-driven decision-making have increasingly relied on prediction market intelligence. Through PolyGram's integration with Polymarket—the globe's most liquid prediction market platform—developers gain programmatic access to comprehensive market datasets suitable for research, journalism, and algorithmic trading.

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 specific outcomes and timeframes
News tools: Identify markets gaining momentum following significant announcements
Aggregators: Benchmark implied probabilities between Polymarket, Kalshi, and Metaculus platforms
Alert systems: Trigger notifications upon substantial market shifts or volatility spikes
Academic research: Leverage resolved market outcomes to evaluate prediction accuracy and model performance

FAQ

Is the Polymarket API free to use?: Absolutely — public market data via the Gamma API incurs no cost, though unauthenticated requests face rate restrictions (approximately 100 per minute). Submitting orders on the CLOB requires an active wallet, though querying order book information remains complimentary.
Is there a Python library for Polymarket?: Multiple community-driven Python packages are available on GitHub. Look for "polymarket-py" repositories to identify the most actively maintained implementations.