{"uid":"cap_Zdnc-WyZAcTeNlZqCni9N","slug":"polymarket-top-markets-by-topic-2a51bd38","name":"Polymarket Top Markets by Topic","description":"Top open Polymarket prediction markets for a topic, ranked by 24h volume: event title, end date, and per-market outcome probabilities (0-1) with USD volume, from the public Gamma API (live on-chain odds). Query: ?tag=crypto|politics|economy|fed|... (any Polymarket tag slug) &limit=1-10 (default crypto, 5). JSON, 5min cache.","url":"https://x402-datashop-production.up.railway.app/v1/predict/polymarket","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","properties":{"tag":{"type":"string","default":"crypto","description":"Polymarket tag slug, e.g. crypto, politics, economy"},"limit":{"type":"integer","default":5,"maximum":10,"minimum":1,"description":"Events to return"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_-TN0kUE84fFuIfx8N5Egz","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns top open Polymarket prediction markets for a given topic tag, ranked by 24-hour volume, with event titles, end dates, and outcome probabilities.","exampleAgentPrompt":"What are the top 5 Polymarket prediction markets for politics right now, including the current odds for each outcome?","exampleUseCases":null,"resultDescription":"A JSON array of up to 10 open Polymarket events for the requested tag, each containing: event title, end date, and a list of outcomes with their current probability (0-1) and 24-hour USD trading volume. Results are cached for 5 minutes and ranked by 24h volume.","failureModes":["Invalid or unrecognized tag slug returns empty results or 404","limit out of range (< 1 or > 10) returns a validation error","Polymarket Gamma API unavailable causes upstream 502/503","Payment not included or insufficient USDC results in 402 Payment Required","Stale data possible within the 5-minute cache window"],"whenToPreferThis":"Use this endpoint when you need live, ranked prediction market odds from Polymarket for a specific topic category. Prefer this over general news or sentiment APIs when you want crowd-sourced probabilistic forecasts backed by real on-chain USD volume. Best for crypto, politics, economics, and Fed-related forecasting questions.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T12:56:24.496Z","isFirstParty":false}