Forecasting applications, quantitative strategies, and financial research increasingly depend on real-time prediction market information. The largest prediction market ecosystem—Polymarket and its underlying CLOB—offers comprehensive APIs that allow developers to construct sophisticated applications atop this infrastructure.
Available APIs
Polymarket Gamma API (Market Data)
Market metadata, current pricing, and historical records are accessible via the Gamma REST API:
- Base URL: https://gamma-api.polymarket.com
- Endpoints: /events, /markets, /positions, /activity
- Authentication: Public market data requires no authentication
- Rate limits: Unauthenticated requests are capped at roughly 100 per minute
Polymarket CLOB API (Order Book & Trading)
Real-time order book snapshots and order placement capabilities are delivered through the CLOB API:
- Base URL: https://clob.polymarket.com
- Endpoints: /book, /trades, /orders, /prices/history
- WebSocket: wss://ws-subscriptions-clob.polymarket.com for live streaming data
- Authentication: Order placement demands ECDSA-signed requests
PolyGram API
PolyGram provides its own interface for authorised trading workflows:
- Complete details available in the PolyGram API Docs
- REST endpoints supporting order execution, account holdings, and market discovery
- API key-based authentication for automated trading strategies
Common Developer Use Cases
- Algorithmic trading: Autonomous portfolio adjustments triggered by external data sources
- Research dashboards: Tracking probability evolution across political or macroeconomic events
- Market aggregators: Cross-platform price comparison and arbitrage identification
- Embedded widgets: Display current prediction odds within editorial or informational websites
- Alert systems: Trigger notifications when market movements exceed specified bounds
Getting Started: Fetch Market Data
Here's a straightforward Python snippet to retrieve active events in real time:
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?
- Market data via the Gamma API carries no cost, subject to rate-limit constraints. Submitting orders through the CLOB API requires a wallet with USDC backing and cryptographic signing, though no separate API charges apply.
- Can I paper trade with the API before risking real USDC?
- Polymarket does not offer a test environment for paper trading. For non-live practice, consider Manifold Markets' API; once ready, migrate to Polymarket or PolyGram's CLOB for actual market participation.
- Are there Python or JavaScript SDKs available?
- Community contributors have built unofficial libraries in both Python and JavaScript for Polymarket integration. Look up "polymarket-py" and "polymarket-js" on GitHub to locate actively maintained versions.