pmxtjs

A unified TypeScript/Node.js SDK for prediction markets - The ccxt for prediction markets.

Installation

npm install pmxtjs

Quick Start

import pmxt from 'pmxtjs';

// Initialize exchanges
const poly = new pmxt.Polymarket();
const kalshi = new pmxt.Kalshi();

// Search for markets
const markets = await poly.fetchMarkets({ query: 'Trump' });
console.log(markets[0].title);

// Get outcome details
const outcome = markets[0].outcomes[0];
console.log(`${outcome.label}: ${(outcome.price * 100).toFixed(1)}%`);

// Fetch historical data (use outcome.outcomeId!)
const candles = await poly.fetchOHLCV(outcome.outcomeId, {
    resolution: '1d',
    limit: 30
});

// Get current order book
const orderBook = await poly.fetchOrderBook(outcome.outcomeId);
const spread = orderBook.asks[0].price - orderBook.bids[0].price;
console.log(`Spread: ${(spread * 100).toFixed(2)}%`);

Core Methods

Market Data

• fetchMarkets(params?) - Get active markets

  // Fetch recent markets
  await poly.fetchMarkets({ limit: 20, sort: 'volume' });
  
  // Search by text
  await poly.fetchMarkets({ query: 'Fed rates', limit: 10 });
  
  // Fetch by slug/ticker
  await poly.fetchMarkets({ slug: 'who-will-trump-nominate-as-fed-chair' });

• fetchEvents(params?) - Get events (groups of related markets)

  await poly.fetchEvents({ query: 'Fed Chair', limit: 5 });

• filterMarkets(markets, query) - Filter markets by keyword

  const events = await poly.fetchEvents({ query: 'Fed Chair' });
  const warsh = poly.filterMarkets(events[0].markets, 'Kevin Warsh')[0];

Deep-Dive Methods

• fetchOHLCV(outcomeId, params) - Get historical price candles
• fetchOrderBook(outcomeId) - Get current bids/asks
• fetchTrades(outcomeId, params) - Get trade history

Helper Methods

• getExecutionPrice(orderBook, side, amount) - Calculate volume-weighted average price
• getExecutionPriceDetailed(orderBook, side, amount) - Get detailed execution info

Trading

Authentication

Polymarket:

const poly = new pmxt.Polymarket({
    privateKey: process.env.POLYMARKET_PRIVATE_KEY,
    proxyAddress: process.env.POLYMARKET_PROXY_ADDRESS, // Optional
    // signatureType: 'gnosis-safe' (default)
});

Kalshi:

const kalshi = new pmxt.Kalshi({
    apiKey: process.env.KALSHI_API_KEY,
    privateKey: process.env.KALSHI_PRIVATE_KEY
});

Limitless:

const limitless = new pmxt.Limitless({
    privateKey: process.env.LIMITLESS_PRIVATE_KEY
});

Trading Methods

• createOrder(params) - Place a new order

  // Using outcome shorthand (recommended)
  await poly.createOrder({
      outcome: market.yes,
      side: 'buy',
      type: 'limit',
      amount: 10,
      price: 0.55
  });

• cancelOrder(orderId) - Cancel an open order

• fetchOrder(orderId) - Get order details

• fetchOpenOrders(marketId?) - Get all open orders

Account Methods

• fetchBalance() - Get account balance
• fetchPositions() - Get current positions

Documentation

For complete API documentation and examples, see:

• API Reference
• Examples
• Setup Guides

Important Notes

• Use outcome.outcomeId, not market.marketId for deep-dive methods (fetchOHLCV, fetchOrderBook, fetchTrades)
• Prices are 0.0 to 1.0 (multiply by 100 for percentages)
• Timestamps are Unix milliseconds
• Volumes are in USD

License

MIT