{"uid":"cap__s_cLXRgQ3M-REp5MyBpF","slug":"polymarket-accuracy-score-33df57fa","name":"Polymarket Accuracy Score","description":"Historical Polymarket crowd accuracy score: % of markets where the final crowd majority correctly predicted the outcome, plus Brier score (calibration quality). Breakdowns by category — crypto, politics, sports, macro, equities, ai. Filter by category and lookback days. $0.004/call — 20% below closest x402 competitor. Source: Polymarket public API (no key required).","url":"https://the-stall.intuitek.ai/cap/polymarket-accuracy-score","method":"GET","headers":{},"bodySchema":{"type":"object","properties":{"properties":{"type":"string"}}},"responseSchema":null,"example":{"request":{"properties":"polymarket_accuracy_score"},"response":{"brier_score":0.0288,"data_source":"Polymarket public API (gamma-api.polymarket.com)","period_days":30,"generated_at":"2026-06-21T05:19:58.955Z","interpretation":"Crowd was correct 96.6% of the time. Excellent calibration (Brier < 0.10).","sample_markets":[{"correct":true,"outcome":"Down","category":"crypto","question":"XRP Up or Down - June 21, 1:00AM-1:15AM ET","crowd_prob":0.07,"volume_usd":1242},{"correct":true,"outcome":"Down","category":"crypto","question":"XRP Up or Down - June 21, 1:10AM-1:15AM ET","crowd_prob":0.1,"volume_usd":991},{"correct":true,"outcome":"Up","category":"crypto","question":"Dogecoin Up or Down - June 21, 1:10AM-1:15AM ET","crowd_prob":0.99,"volume_usd":253},{"correct":true,"outcome":"Down","category":"equities","question":"Hyperliquid Up or Down - June 21, 1:00AM-1:15AM ET","crowd_prob":0.16,"volume_usd":299},{"correct":true,"outcome":"Up","category":"crypto","question":"Dogecoin Up or Down - June 21, 1:00AM-1:15AM ET","crowd_prob":0.999,"volume_usd":360},{"correct":true,"outcome":"Over","category":"other","question":"Trevor Rogers: Strikeouts O/U 1.5","crowd_prob":0.999,"volume_usd":14}],"markets_analyzed":295,"category_breakdown":[{"markets":141,"category":"crypto","brier_score":0.0099,"accuracy_pct":99.3},{"markets":107,"category":"other","brier_score":0.0221,"accuracy_pct":98.1},{"markets":39,"category":"equities","brier_score":0.1084,"accuracy_pct":84.6},{"markets":7,"category":"sports","brier_score":0.0707,"accuracy_pct":85.7},{"markets":1,"category":"politics","brier_score":0,"accuracy_pct":100}],"overall_accuracy_pct":96.6}},"exampleRequest":{"properties":"polymarket_accuracy_score"},"tags":["x402"],"displayCostAmount":"0.004","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"settled","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":"$0.004/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.034","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.034","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_-I-bnBwLBBbJxLcjXEvVn","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.034","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns an accuracy or calibration score for Polymarket prediction market forecasts or participants","exampleAgentPrompt":"Can you pull the accuracy score for Polymarket on the 2024 US election markets — I want to know how well-calibrated their crowd predictions turned out to be?","exampleUseCases":null,"resultDescription":"A numeric accuracy or calibration score reflecting how well Polymarket predictions aligned with actual outcomes, potentially including breakdown metrics for the specified market or forecaster.","failureModes":["Unknown or invalid Polymarket market ID returns an error or empty result","Market still open with no resolved outcome cannot be scored","Insufficient data for scoring if market had very low volume","Payment failure or insufficient USDC balance blocks the request","Malformed input schema returns 400-level error"],"whenToPreferThis":"Use this endpoint when you need a quantitative measure of Polymarket's forecasting accuracy or calibration for a specific market or participant, especially without wanting to manage API keys or accounts — paying $0.004 USDC per call via x402 on Base mainnet.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T06:47:28.441Z","isFirstParty":false}