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

In this guide

Available Data Endpoints
Python Quickstart
Use Cases
FAQ

Developers, analysts, and researchers increasingly rely on prediction market intelligence for strategic decision-making and empirical studies. The Polymarket platform, available through PolyGram, offers comprehensive APIs that unlock access to the globe's most substantial prediction market dataset for builders seeking to integrate this data into their 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 how prediction probabilities evolve throughout an event's lifecycle
News tools: Identify markets experiencing significant shifts in response to emerging information
Aggregators: Benchmark implied probabilities across Polymarket, Kalshi, and Metaculus platforms
Alert systems: Trigger notifications whenever market movements exceed predefined parameters
Academic research: Leverage historical settlement records to evaluate prediction accuracy and model performance

FAQ

Is the Polymarket API free to use?: Absolutely — market data via the Gamma API is available at no cost subject to standard rate limits (approximately 100 requests per minute without authentication). Submitting orders on the CLOB requires wallet funding; however, all data retrieval operations remain complimentary.
Is there a Python library for Polymarket?: Multiple community-developed Python packages are available on GitHub. Look for "polymarket-py" repositories to find actively maintained implementations.