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VerityLayer Pro Verification
x402
VerityLayer Pro Verification is a paid API for AI agents from api.veritylayer.dev, paid per call via x402, $0.35/call, status unknown (last checked 2026-09-13).
Verifies AI-generated claims and citations against authoritative sources, returning a verdict, supporting evidence, reasoning, and a confidence score.
Price / call$0.35
Success—
StatusUnknown
How this service works
VerityLayer verifies whether a factual claim is true — fact-check, verify a claim, is this true. Independent, fail-closed verification for AI agents: returns a verdict (supported/unsupported/uncertain), a calibrated 0-1 confidence, reasoning, and evidence; abstains rather than guess. Every verdict includes an Ed25519-signed receipt — portable cryptographic proof of what was verified, free re-verification at /receipt/verify. Tier: pro — grounded premium synthesis (Opus).
Output
A JSON object containing: a 'verdict' field (e.g. 'supported', 'refuted', 'unverifiable'), an 'evidence' array of authoritative source references that back the verdict, a 'reasoning' string explaining the determination, and a 'confidence' score between 0 and 1 indicating certainty.
Example use cases
Example prompt
“Can you run this through VerityLayer to check if it's actually true: 'The Mata v. Avianca case was decided by Judge P. Kevin Castel of the Southern District of New York in 2023'? I need to know the verdict, what evidence supports or refutes it, and how confident the system is.”
Technical details
Endpoint
POSThttps://api.veritylayer.dev/verify/proWhen to prefer
Choose VerityLayer when you need a fail-closed, independent verification pass on AI-generated claims or citations before they reach end users — especially in legal, academic, journalistic, or compliance contexts where hallucinated sources carry serious risk. It is particularly suited when you need structured evidence and reasoning alongside a verdict, not just a binary pass/fail. Prefer it over generic search-based fact-checking when you want auditable, confidence-scored outputs with zero false-positive tolerance.
Side effects
- Claim too vague or ambiguous to verify — returns low confidence or 'unverifiable' verdict
- Source material unavailable or paywalled — may limit evidence breadth
- Highly niche or recent claims may lack sufficient authoritative sources to assess
- Malformed or missing claim input — returns validation error
- Rate limit or payment failure — returns 402 or 429 status
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| claim | string | |
| context | string |
Output
Schema · Response
{
"type": "json",
"example": {
"verdict": "supported",
"evidence": [
"Encyclopaedia Britannica — Eiffel Tower, Paris, France."
],
"reasoning": "Multiple authoritative sources place the Eiffel Tower on the Champ de Mars in Paris, France.",
"confidence": 0.97
}
}Tags
x402
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