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Polymarket–Kalshi Arbitrage Spread Finder
x402
Polymarket–Kalshi Arbitrage Spread Finder is a paid API for AI agents from x402.agentutility.ai, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).
Finds arbitrage opportunities by cross-referencing matching prediction market questions on Polymarket and Kalshi and surfacing probability spreads between them.
Price / call$0.02
Success—
StatusUnknown
How this service works
Paid x402 endpoints organized into product clusters. USDC-settled on Base. MCP-callable. ERC-8004 identity registry agentId 47167.
Output
Returns a list of matched question pairs found across both platforms, each with a match score, the yes-probability on each platform, the spread value, the spread direction (e.g. polymarket_higher), and both platforms' question titles. Also includes the total pair count and data attribution.
Example use cases
Example prompt
“Can you scan Polymarket and Kalshi right now and show me which matched prediction market questions have the biggest probability spread between the two platforms — I want to find arbitrage opportunities.”
Technical details
Endpoint
POSThttps://x402.agentutility.ai/polymarket-kalshi-arbitrageWhen to prefer
Use this endpoint when you need a real-time, cross-platform comparison of prediction market probabilities specifically between Polymarket and Kalshi. Prefer this over manually querying each platform's API when you want pre-matched pairs with spread calculations already computed and ready to act on.
Side effects
- Kalshi or Polymarket API unavailable — empty pairs list or partial results
- No matching questions found above threshold — returns empty pairs array
- Payment not received — x402 payment required error before data is returned
- Low match_score pairs only — semantic matching may miss non-obvious equivalents
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"pairs": [
{
"spread": 0.07,
"match_score": 0.5,
"kalshi_title": "Will X win the presidential election?",
"poly_question": "Will X win the election?",
"poly_yes_prob": 0.62,
"kalshi_yes_prob": 0.55,
"spread_direction": "polymarket_higher"
}
],
"pair_count": 1,
"attribution": "Data: Polymarket gamma-api + Kalshi public API."
}
}Tags
x402
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