Polymarket vs Kalshi MCP Server

Give your AI agent the same prediction market on Polymarket and Kalshi, matched and verified, with both prices, the gap between them, the pre-fee edge, alerts when a gap opens, and 30-day price history.

• 10,000+ verified pairs across elections, politics, economics, crypto and sports

• Sports line by line: game winners, spreads and totals in 100+ leagues (NFL, NBA, NHL, college, soccer, esports)

• Gap alerts: pairs whose gap just opened, newest first

• Refreshed every hour

Hosted remote MCP server (Streamable HTTP) running on Apify. Nothing to install.

Connect

Server URL:

https://mcp.apify.com?tools=forgedata/prediction-markets-api

Claude: add the URL as a custom connector, then sign in to Apify when asked. A free Apify account works.

Cursor, VS Code, Windsurf and other clients:

{
  "mcpServers": {
    "polymarket-kalshi": {
      "url": "https://mcp.apify.com?tools=forgedata/prediction-markets-api"
    }
  }
}

Prefer a token over sign-in? Add "headers": { "Authorization": "Bearer YOUR_APIFY_TOKEN" }.

Related MCP server: parsec-mcp

Things to ask your agent

• "Find markets that are on both Polymarket and Kalshi with a gap over 5 cents that traded today."

• "Which NBA spreads tonight differ most between Polymarket and Kalshi?"

• "Show me gap alerts from the last hour, politics only."

• "What are Polymarket and Kalshi pricing for control of the Senate?"

How matching works

Questions are matched on their wording with strict checks: numbers, years and dates must agree, words like "not" or "before" or a party name must appear on both sides, and every named person or place must appear on both sides. Sports games are matched by league, date and both teams, then each winner, spread and total line is paired with the exact same line on the other platform. Gaps are only reported when both sides show a live quote, so empty order books do not show up as fake opportunities.

Pricing

Pay per result through your Apify account: $3.00 per 1,000 results, lower on Apify's paid tiers. Apify's free plan includes monthly usage credit.

Also available as a REST API

• RapidAPI: https://rapidapi.com/gblackman10/api/polymarket-vs-kalshi

• Apify: https://apify.com/forgedata/prediction-markets-api

Notes

Data comes from the public market data both platforms publish. Not affiliated with Polymarket or Kalshi. Resolution rules can differ in the details between platforms, so read both before trading. Information only, not financial advice.

Built by Data Forge. MIT license.