Polymarket & Kalshi Arbitrage, Odds & Whale Radar

Extract real-time Polymarket and Kalshi prediction market probabilities, synthetic Dutch-book cross-venue arbitrage spreads, orderbook bid-ask depth, and high-conviction whale trade fills in a single normalized JSON feed. Built by Enigma Labs for quantitative trading desks, financial researchers, newsletter authors, and autonomous AI Agents (mcp.apify.com)—executing in seconds with zero headless browser overhead.

What does Polymarket & Kalshi Arbitrage, Odds & Whale Radar do?

Prediction market liquidity is split between crypto-native orderbooks (Polymarket CLOB) and US CFTC-regulated event contracts (Kalshi v2). Because retail and institutional capital react at different speeds on each exchange, identical macro, political, crypto, tech, and sports events frequently trade at divergent implied probabilities.

This Actor queries both venues simultaneously, normalizes heterogeneous schemas (outcomePrices vs yes_ask_dollars / no_ask_dollars), and delivers ready-to-trade signals:

Capability	Details
Cross-Venue Arbitrage Matcher	Pairs overlapping Polymarket and Kalshi contracts via token-similarity scoring and computes synthetic Dutch-book cost (YES_VenueA + NO_VenueB < $1.00) plus raw probability divergence (arb_edge_pct).
Unified Dual-Venue Odds	Converts Polymarket Gamma/CLOB contracts and Kalshi v2 dollar orderbooks into one clean schema (yes_price, no_price, volume_usd, liquidity_usd).
Live Whale Orderflow Tape	Tracks large cash fills above your min_whale_usd threshold (default $2,500+) with direction (BUY/SELL), outcome, share size, and transaction hash.
Zero-Browser Cloud Speed	Runs natively in < 5 seconds on minimal RAM (128–256 MB) with $0 proxy overhead.

Why use this Actor? (Top Use Cases)

• Quantitative & Arbitrage Bots: Schedule every 5–15 minutes via Apify Schedules or Webhooks to alert your Slack, Telegram, or execution engine whenever arb_edge_pct exceeds transaction and settlement fees.
• AI Agents & MCP Workflows: Connect directly to Claude Desktop, Cursor, OpenAI Agents, or LangGraph via https://mcp.apify.com so your AI research copilot can answer "What are the current Polymarket vs Kalshi odds on the next Fed rate decision, and are whales buying YES?" with live numbers.
• Macro, Crypto & Election Dashboards: Pipe normalized implied probabilities and 24-hour volume straight into Google Sheets, Notion, Supabase, or BI dashboards.
• Smart-Money & Newsletter Alpha: Surface the largest $10,000+ whale positions of the day automatically for daily market intelligence briefings.

How much does it cost?

This Actor uses transparent Pay-Per-Event (PPE) pricing ($0.003 per emitted signal, or $3.00 per 1,000 signals) so you only pay for real data delivered:

• Quick Radar Scan (~35 signals): ~$0.10 total
• Deep Quant Sweep (~200 signals): ~$0.60 total
• Apify Free Plan ($5/month free credit): Covers ~1,600+ live market, arbitrage, and whale signals every month at zero out-of-pocket cost.
• Zero Charge on Empty Queries: If a niche keyword filter matches zero active contracts, a clean diagnostic status row is returned with $0 event charge.

Input parameters

Click Try for free with default settings for an instant cross-venue scan, or customize your run with these parameters:

• mode (select, default: "all"): Choose "all" (arbitrage + odds + whales), "arbitrage_and_markets", or "whale_trades_only".
• search_query (string, optional): Filter contracts by keyword such as "Bitcoin", "Fed", "Inflation", "Trump", or "AI". Leave empty to scan the highest-volume live markets.
• max_markets_per_venue (integer, default: 25): Maximum active contracts fetched per exchange (5 to 200).
• min_whale_usd (integer, default: 2500): Minimum cash notional in USD required to include a Polymarket whale trade.
• max_whale_trades (integer, default: 10): Maximum number of live whale trades returned per run.

Example Input JSON

{
  "mode": "all",
  "search_query": "Bitcoin",
  "max_markets_per_venue": 25,
  "min_whale_usd": 2500,
  "max_whale_trades": 10
}

Output example

Results are saved to the default Dataset and can be exported in JSON, CSV, Excel, XML, or RSS formats via Console or REST API:

[
  {
    "record_type": "cross_venue_arbitrage",
    "venue": "Polymarket x Kalshi",
    "title": "Fed rate cut at next FOMC meeting?  <->  Federal Reserve rate cut",
    "category": "Macro & Economics",
    "yes_price": 0.61,
    "no_price": 0.36,
    "kalshi_yes_price": 0.64,
    "arb_edge_pct": 3.0,
    "volume_usd": 1482900.5,
    "liquidity_usd": 412000.0,
    "strategy_hint": "PM YES ($0.61) + Kalshi NO ($0.36) = $0.970 | Prob Δ=3.0%",
    "url": "https://polymarket.com",
    "scraped_at": "2026-11-15T01:00:00Z"
  },
  {
    "record_type": "whale_trade",
    "venue": "Polymarket Whale Tape",
    "title": "[BUY YES] Will Bitcoin reach $150,000 this year?",
    "category": "Whale Orderflow",
    "yes_price": 0.42,
    "no_price": 0.58,
    "arb_edge_pct": 0.0,
    "volume_usd": 14700.0,
    "liquidity_usd": 35000.0,
    "strategy_hint": "Whale BUY 35,000 shares of 'YES' @ $0.420 ($14,700.00)",
    "url": "https://polymarket.com",
    "scraped_at": "2026-11-15T01:00:00Z"
  }
]

Integrations: AI Agents (MCP) & Python API

Because this Actor runs under strict LIMITED_PERMISSIONS with full Input, Output, and Dataset schemas, it works seamlessly with Apify's MCP Server (https://mcp.apify.com) as well as standard REST/SDK pipelines:

from apify_client import ApifyClient

client = ApifyClient("YOUR_APIFY_API_TOKEN")
run = client.actor("enigmalabs/polymarket-kalshi-arbitrage-scraper").call(
    run_input={"mode": "all", "max_markets_per_venue": 30, "min_whale_usd": 5000}
)
for item in client.dataset(run["defaultDatasetId"]).iterate_items():
    print(item["record_type"], item["title"], item["arb_edge_pct"])

Frequently Asked Questions (FAQ) & Disclaimer

• Do I need an API key for Polymarket or Kalshi, or paid proxies? No. All public orderbook, event, and trade feeds are queried directly from cloud infrastructure with zero extra credentials or proxy fees required.
• Are cross-venue matches guaranteed risk-free arbitrage? Always inspect exact contract resolution rules on both exchanges before trading—similar headlines can occasionally carry different settlement dates or oracle definitions.

Legal Notice: Independent market data extraction tool maintained by Enigma Labs. Not affiliated with, endorsed by, or sponsored by Adventure One QSS Inc. (Polymarket) or KalshiEX LLC (Kalshi). Provided strictly for informational and quantitative research purposes, not financial or investment advice.