pmxtjs

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

Installation

``bash
npm install pmxtjs
`

Quick Start

`typescript
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

$3

- fetchMarkets(params?) - Get active markets
`typescript
// 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)
`typescript
await poly.fetchEvents({ query: 'Fed Chair', limit: 5 });
`

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

$3

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

$3

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

Trading

$3

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

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

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

$3

- createOrder(params) - Place a new order
`typescript
await poly.createOrder({
marketId: market.marketId,
outcomeId: outcome.outcomeId,
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

$3

- 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