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Overview

Connect to receive real-time market data for all markets within a specific event, including bid/ask prices, volume, and open interest.

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Connection

wss://api.bison.markets/ws/kalshi/event/{eventTicker}
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eventTicker
string
required
The Kalshi event ticker (e.g., KXBTC-100K)

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Example Connection

const eventTicker = "KXBTC-100K";
const ws = new WebSocket(
  `wss://api.bison.markets/ws/kalshi/event/${eventTicker}`
);

ws.onopen = () => {
  console.log(`Connected to ${eventTicker} market data`);
  
  // Send heartbeat every 30 seconds
  setInterval(() => {
    if (ws.readyState === WebSocket.OPEN) {
      ws.send(JSON.stringify({ type: "ping" }));
    }
  }, 30000);
};

ws.onmessage = (event) => {
  const data = JSON.parse(event.data);
  
  // Ignore ping/pong messages
  if (data.type === "ping" || data.type === "pong") {
    return;
  }
  
  console.log("Market update:", data);
  updateMarketDisplay(data);
};

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Ticker Update Format

Ticker updates contain the latest market data: 
{
  "market_ticker": "KXBTC-100K-DEC31",
  "yes_bid_uusdc": "720000",
  "yes_ask_uusdc": "750000",
  "no_bid_uusdc": "250000",
  "no_ask_uusdc": "280000",
  "last_price_uusdc": "735000",
  "volume": 15000,
  "open_interest": 50000
}

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Response Fields

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market_ticker
string
Market ticker being updated
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yes_bid_uusdc
string
Best bid price for YES in µUSDC (integer string)
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yes_ask_uusdc
string
Best ask price for YES in µUSDC (integer string)
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no_bid_uusdc
string
Best bid price for NO in µUSDC (integer string)
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no_ask_uusdc
string
Best ask price for NO in µUSDC (integer string)
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last_price_uusdc
string
Last traded price in µUSDC (integer string)
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volume
number
Total traded volume
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open_interest
number
Current open interest (outstanding contracts)
To avoid ambiguity, we denote the smallest possible multiple of USDC (0.000001 USDC) as one uusdc, which stands for µUSDC (micro-USDC), and denote the smallest possible multiple of a contract (0.01 contract) as one ccontract (centicontract).User-facing USDC balances are specified as fixed-point strings (e.g. "1.2625" for USDC). Contract quantities in the API and SDK are specified as integer ccontracts strings (e.g. "1050" for 10.50 contracts at precision 2).

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Example: Building a Price Display

const eventTicker = "KXBTC-100K";
const ws = new WebSocket(
  `wss://api.bison.markets/ws/kalshi/event/${eventTicker}`
);

// Store market data
const markets = new Map();

ws.onmessage = (event) => {
  const data = JSON.parse(event.data);
  
  if (data.type === "ping" || data.type === "pong") {
    return;
  }
  
  // Update market data
  markets.set(data.market_ticker, {
    yesBid: data.yes_bid_uusdc ? Number(data.yes_bid_uusdc) / 1_000_000 : null,
    yesAsk: data.yes_ask_uusdc ? Number(data.yes_ask_uusdc) / 1_000_000 : null,
    noBid: data.no_bid_uusdc ? Number(data.no_bid_uusdc) / 1_000_000 : null,
    noAsk: data.no_ask_uusdc ? Number(data.no_ask_uusdc) / 1_000_000 : null,
    lastPrice: data.last_price_uusdc ? Number(data.last_price_uusdc) / 1_000_000 : null,
    volume: data.volume,
    openInterest: data.open_interest,
  });
  
  // Update your UI
  renderMarketData(data.market_ticker, markets.get(data.market_ticker));
};

function renderMarketData(ticker, data) {
  console.log(`${ticker}:`);
  console.log(`  YES: ${data.yesBid} bid / ${data.yesAsk} ask`);
  console.log(`  NO:  ${data.noBid} bid / ${data.noAsk} ask`);
  console.log(`  Last: ${data.lastPrice}, Volume: ${data.volume}`);
}

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Use Cases

Live Price Feeds

Display real-time bid/ask spreads for markets in an event

Trading Dashboards

Build comprehensive market overviews with live data

Price Alerts

Trigger notifications when prices reach certain thresholds

Market Analytics

Track volume and liquidity changes in real-time