{"uid":"cap_bBAC21a1VxsEQve6Bj9I1","slug":"three-ws-fact-check-api-4ae8edee","name":"three.ws Fact-Check API","description":"Make a 3D AI agent from a selfie in 60 seconds. Drop one HTML tag to embed it on any website. Agents think on IBM watsonx.ai (Granite); optionally charge per chat with built-in micropayments.","url":"https://three.ws/api/x402/fact-check","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"claim":{"type":"string","maxLength":1000,"minLength":5,"description":"The factual claim to verify."},"imageUrl":{"type":"string","format":"uri","maxLength":2048,"description":"Optional http(s) image attached as evidence (a chart, screenshot, label, or photo). A vision model describes it, transcribes any visible text, and weighs its stance toward the claim alongside web sources. Ignored if vision is unavailable."},"strictness":{"enum":["high","medium","low"],"type":"string","default":"medium","description":"high: penalizes low-authority sources. medium: default. low: accepts all sources equally."}}},"responseSchema":{"type":"json","example":{"lane":"paid","claim":"The Eiffel Tower is 330 meters tall.","sources":[{"url":"https://en.wikipedia.org/wiki/Eiffel_Tower","title":"Eiffel Tower - Wikipedia","stance":"supports","weight":0.7,"excerpt":"The tower is 330 m (1,083 ft) tall, including a 24 m (79 ft) antenna.","retrievedAt":"2026-05-27T00:00:00.000Z"}],"verdict":"contradicted","confidence":0.78,"strictness":"high","attestation":"sha256:abcdef1234567890...","costBreakdown":{"llmTokens":1420,"totalUsdc":"0.100355","searchCalls":3}}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.1","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":"$0.1/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.1","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.1","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_rlvGpBu8r3D-Kr4CF2-xY","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.1","costPer":"request","priority":0,"asset":"EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Verifies a textual claim against live web sources and returns a verdict, confidence score, supporting excerpts, and a cryptographic attestation.","exampleAgentPrompt":"Can you fact-check this claim for me using high strictness: 'The Eiffel Tower is 330 meters tall'? I want to know the verdict, confidence score, and which sources support or contradict it.","exampleUseCases":[{"title":"Verify customer testimonial authenticity","prompt":"I need you to fact-check this customer review claim: 'Our product reduced processing time by 80% for enterprise clients.' Can you tell me if this is supported by our case studies or third-party reports, and give me a confidence score?"},{"title":"Check social media claim before sharing","prompt":"Before I repost this, can you verify if it's true? The claim is: 'Electric vehicles produce 50% fewer emissions than gas cars over their lifetime.' I need the verdict, confidence, and sources that back it up or contradict it."},{"title":"Validate financial advisor recommendation","prompt":"A financial advisor told me that 'Gold prices have increased 300% over the last decade.' Can you fact-check this with current data and give me a confidence score plus the sources you find?"}],"resultDescription":"Returns a JSON object with the original claim, a verdict (e.g. 'supported', 'contradicted', 'unverifiable'), a confidence score (0-1), a list of web sources each with URL, title, stance, weight, and excerpt, a cryptographic SHA-256 attestation of the result, and a cost breakdown showing LLM tokens used, search calls made, and total USDC spent.","failureModes":["Claim is too vague or ambiguous for web sources to resolve — low confidence verdict returned","No relevant sources found — verdict may be 'unverifiable'","Payment of 0.1 USDC not provided or rejected — 402 Payment Required response","LLM or search backend unavailable — 5xx error","Claim contains harmful or disallowed content — request rejected","Attestation generation failure — partial result without cryptographic proof"],"whenToPreferThis":"Choose this endpoint when you need a verifiable, source-backed verdict on a specific factual claim, especially when you need a cryptographic attestation for auditability. Prefer it over general web search when you want a structured true/false/contradicted/unverifiable verdict with confidence scoring and per-source stance attribution rather than raw search results.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T12:49:39.035Z","isFirstParty":false}