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Guide

Prediction Market APIs for Developers: Access Live Market Data & Order Books

PolyGram and Polymarket provide REST and WebSocket APIs for prediction market data. Build trading bots, analytics tools, and dashboards with live CLOB data.

Priya Anand
Sports Editor — Odds & Form · · 2 min read
✓ Fact-checked · 📅 Updated 1 May 2026 · 2 min read
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Forecasting applications, quantitative research, and algorithmic trading strategies increasingly depend on real-time prediction market data. PolyGram and the Polymarket CLOB infrastructure provide robust APIs enabling developers to integrate with the world's most liquid prediction market platform.

Available APIs

Polymarket Gamma API (Market Data)

The Gamma REST API delivers event information, current pricing, and time-series market data:

  • Base URL: https://gamma-api.polymarket.com
  • Endpoints: /events, /markets, /positions, /activity
  • Authentication: None required for public market data
  • Rate limits: ~100 requests/minute for unauthenticated access

Polymarket CLOB API (Order Book & Trading)

The CLOB API grants access to live order book snapshots and order placement functionality:

  • Base URL: https://clob.polymarket.com
  • Endpoints: /book, /trades, /orders, /prices/history
  • WebSocket: wss://ws-subscriptions-clob.polymarket.com for real-time updates
  • Authentication: ECDSA-signed requests required for order submission

PolyGram API

PolyGram offers its proprietary API for authenticated trading and account operations:

  • See full documentation at PolyGram API Docs
  • REST endpoints for trade placement, portfolio data, and market browse
  • API key authentication for programmatic trading

Common Developer Use Cases

  • Algorithmic trading: Automated position management based on external signals
  • Research dashboards: Historical probability tracking for election or economic forecasts
  • Market aggregators: Comparing prediction market prices across platforms
  • Embedded widgets: Show live prediction market odds on news sites or blogs
  • Alert systems: Notify when a market moves beyond a threshold

Getting Started: Fetch Market Data

A basic Python example to fetch live events:

import requests
response = requests.get(
    "https://gamma-api.polymarket.com/events",
    params={"limit": 10, "active": "true", "order": "volume24hr"}
)
events = response.json()
for event in events:
    print(event["title"], event["volume"])

FAQ

Is the Polymarket API free to use?
Yes — market data (Gamma API) is free with rate limits. Order submission (CLOB API) requires a funded wallet and ECDSA authentication but has no additional fees.
Can I paper trade with the API before risking real USDC?
Polymarket doesn't have a sandbox environment. Use Manifold Markets API for paper trading, then transition to Polymarket/PolyGram CLOB for live trading.
Are there Python or JavaScript SDKs available?
The community has developed unofficial Python and JS libraries for Polymarket. Search GitHub for "polymarket-py" and "polymarket-js" for the latest maintained options.
Priya Anand
Sports Editor — Odds & Form

Priya benchmarks sports prediction-market lines against traditional sportsbooks. Specialism: Premier League, NBA, and the major European cup competitions.