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AsterPay Fact-Check API
x402
AsterPay Fact-Check API is a paid API for AI agents from x402.asterpay.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).
Verifies factual claims against sources using an LLM, returning a verdict, evidence, confidence score, and summary
Price / call$0.001
Success—
StatusUnknown
How this service works
Source-bounded fact-check. Verify a claim against provided source text. Returns verdict: supported, contradicted, or unverifiable. Does NOT search the web.
Output
Returns a JSON object with: verdict (e.g. 'contradicted', 'supported', 'unverifiable'), a plain-English summary, the evidence used to reach the verdict, a confidence score (0–1), the LLM model used, latency in milliseconds, and the number of claims checked.
Example use cases
Verify earnings claims in financial reports
“Before we publish this investor briefing, can you fact-check these numbers? We're claiming that Tesla's Q3 revenue hit $25.2B — I need to know if that's actually true or if we're off.”
Detect misinformation in customer testimonials
“We got this customer review saying our competitor was sued by regulators in 2022 — can you verify if that actually happened? I want to make sure we're not spreading false claims about them.”
Validate statistics before marketing campaign
“Our marketing team wants to use this stat in our ads: 'Remote workers are 37% more productive.' Can you fact-check that against reliable sources and tell me how confident you are it's accurate?”
Technical details
Endpoint
POSThttps://x402.asterpay.io/v2/x402/ai/fact-checkWhen to prefer
Choose this endpoint when an AI agent needs to verify a specific factual claim (e.g. a revenue figure, a statistic, a quoted fact) against real sources, and requires a structured verdict with evidence and confidence. Prefer over generic LLM prompting when you need a structured, auditable fact-check response with a clear verdict enum and supporting evidence, especially in agentic pipelines requiring trustworthy, verifiable outputs.
Side effects
- Claim is too vague or ambiguous to verify — low confidence score returned
- Source data unavailable or outdated — verdict may be 'unverifiable'
- Rate limit exceeded — 402 or 429 response
- Malformed request body — 400 error
- Payment not accepted or insufficient USDC — 402 payment required error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| claim | string | |
| source | string |
Output
Schema · Response
{
"type": "json",
"example": {
"model": "llama-3.3-70b-versatile",
"summary": "Revenue figure directly contradicted by source.",
"verdict": "contradicted",
"evidence": "Source states $119.6B, not $94.9B as claimed.",
"confidence": 0.98,
"latency_ms": 820,
"claims_checked": 1
}
}Tags
x402
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