Polymarket API Guide: Build Trading Bots and Analysis Tools

Want to build on top of Polymarket? Their API enables automated trading, custom dashboards, and sophisticated analysis tools. Here is everything developers need to know.

API Overview

Polymarket offers several APIs for different use cases:

• CLOB API: Central Limit Order Book for trading
• Gamma API: Market data and metadata
• Subgraph: On-chain historical data via GraphQL
• REST endpoints: General market information

Most developers start with the Gamma API for reading data, then move to the CLOB API for trading.

Getting Market Data

The Gamma API provides market information without authentication:

// Fetch all active markets
fetch('https://gamma-api.polymarket.com/markets')
  .then(r => r.json())
  .then(markets => console.log(markets));

// Fetch specific market by condition ID
fetch('https://gamma-api.polymarket.com/markets/[condition-id]')
  .then(r => r.json())
  .then(market => console.log(market));

The response includes market title, description, outcomes, current prices, volume, and resolution criteria.

Order Book Data

For real-time order book data, use the CLOB API:

// Get order book for a token
fetch('https://clob.polymarket.com/book?token_id=[token-id]')
  .then(r => r.json())
  .then(book => {
    console.log('Bids:', book.bids);
    console.log('Asks:', book.asks);
  });

This provides bid and ask depth, essential for understanding liquidity and potential slippage.

Historical Data

The Polymarket subgraph on The Graph provides historical on-chain data:

// GraphQL query for historical trades
query {
  trades(first: 100, orderBy: timestamp, orderDirection: desc) {
    id
    price
    size
    timestamp
    market {
      question
    }
  }
}

Historical data is valuable for backtesting strategies and analyzing market behavior patterns.

Building a Trading Bot

Automated trading requires authentication and signing orders:

1. Create API key: Generate credentials in your Polymarket account
2. Sign orders: Use your wallet to sign EIP-712 messages
3. Submit orders: POST to the CLOB API
4. Monitor fills: Poll for order status updates

Note: Automated trading carries significant risks. Start with paper trading and small positions.

Rate Limits

Be aware of API rate limits to avoid being throttled:

• Public endpoints: Generally generous limits
• Authenticated endpoints: Higher limits with API key
• Order submission: More restrictive to prevent spam

Implement exponential backoff and caching to stay within limits.

Use Cases

Common applications built on the Polymarket API:

• Price alerts: Notify when markets move significantly
• Portfolio tracking: Monitor positions across markets
• Arbitrage bots: Exploit price differences automatically
• Analytics dashboards: Visualize market data and trends
• AI analysis: Feed data to models for predictions
• Discord/Telegram bots: Share market updates in communities

Libraries and SDKs

Community and official resources for development:

• py-clob-client: Official Python client for CLOB API
• polymarket-sdk: Community TypeScript SDK
• ethers.js: For wallet and signing operations
• viem: Modern alternative to ethers.js

Best Practices

Tips for building reliable Polymarket integrations:

• Handle errors gracefully: API can be temporarily unavailable
• Cache when possible: Reduce API calls for static data
• Validate all inputs: Protect against malformed responses
• Log everything: Debug issues with comprehensive logs
• Test with small amounts: Verify trading logic before scaling
• Monitor positions: Track open orders and fills

Security Considerations

Protect your API credentials and funds:

• Never commit keys: Use environment variables
• Separate wallets: Use dedicated trading wallets
• Limit permissions: Only grant necessary access
• Audit regularly: Review bot activity and positions
• Kill switch: Implement emergency shutdown

Why Build When You Can Use Polifly?

Building your own analysis tools is educational, but time-consuming. Polifly provides AI-powered analysis that would take thousands of development hours to replicate:

• Real-time market analysis without coding
• AI probability estimation across all markets
• Identified edge opportunities updated continuously
• No API rate limits or infrastructure to manage

Focus on trading while we handle the technical complexity.

Key Takeaways

• Gamma API for market data, CLOB API for trading
• GraphQL subgraph provides historical data
• Rate limits require careful implementation
• Security is critical for automated trading
• Consider using existing tools before building custom

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