{"uid":"cap_LJ3luwjii4DPhwSe5ob-w","slug":"polymarket-kalshi-arbitrage-spread-finder-2648f7f0","name":"Polymarket–Kalshi Arbitrage Spread Finder","description":"Paid x402 endpoints organized into product clusters. USDC-settled on Base. MCP-callable. ERC-8004 identity registry agentId 47167.","url":"https://x402.agentutility.ai/polymarket-kalshi-arbitrage","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method","bodyType","body"],"properties":{"body":{"properties":{"category":{"type":"string","description":"Optional Polymarket category filter (substring)."},"min_spread":{"type":"number","description":"Minimum |p_poly - p_kalshi| spread to report. 0-1. Default 0.05."},"scan_limit":{"type":"number","description":"Max markets to pull from each venue. 10-500. Default 100."},"min_match_score":{"type":"number","description":"Minimum Jaccard token overlap to treat two titles as the same event. 0-1. Default 0.4."}}},"type":{"type":"string","const":"http"},"method":{"enum":["POST"],"type":"string"},"bodyType":{"enum":["json","form-data","text"],"type":"string"}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"pairs":{"type":"array","items":{"type":"object","properties":{"spread":{"type":"number"},"match_score":{"type":"number"},"kalshi_title":{"type":"string"},"poly_question":{"type":"string"},"poly_yes_prob":{"type":"number"},"kalshi_yes_prob":{"type":"number"},"spread_direction":{"type":"string"}}}},"pair_count":{"type":"integer"},"attribution":{"type":"string"}}}}}}},"responseSchema":{"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."}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"registry","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_A5UjR3peZIHf0Pmd20gIF","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Finds arbitrage opportunities by cross-referencing matching prediction market questions on Polymarket and Kalshi and surfacing probability spreads between them.","exampleAgentPrompt":"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.","exampleUseCases":null,"resultDescription":"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.","failureModes":["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"],"whenToPreferThis":"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.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T13:13:16.555Z","isFirstParty":false}