Claim Verification

Fact-check any statement against multiple authoritative sources. SignalStack cross-references the claim across Wikipedia, Google Fact Check Tools, Semantic Scholar, GDELT news database, and general web search to produce a trust score and evidence chain.

Endpoint

POST https://signal-stack-ten.vercel.app/v1/verify/claim

Request parameters

Parameter	Type	Required	Description
`claim`	string	Yes	The statement to verify (max 2,000 characters)
`sources`	string[]	No	Sources to query: `web`, `wikipedia`, `google_fact_check`,`semantic_scholar`, `gdelt` (default: all)
`language`	string	No	ISO 639-1 language code (default: `en`)
`max_evidence`	integer	No	Maximum evidence items to return (1–20, default: 5)

Response schema

Field	Type	Description
`id`	string	Unique request identifier
`trust_score`	number	Overall confidence in the claim (0.0–1.0)
`verdict`	string	`true`, `false`, `unverifiable`, `conflicting`
`evidence`	array	List of supporting and refuting sources
`dimensions`	object	Per-dimension trust sub-scores
`latency_ms`	number	Processing time in milliseconds
`credits_used`	number	Credits consumed by this request

Request example

{
  "claim": "The Great Wall of China is visible from space with the naked eye",
  "sources": ["web", "wikipedia", "google_fact_check"],
  "language": "en",
  "max_evidence": 5
}

Response example

{
  "id": "vrf_clm_g3h4i5j6",
  "trust_score": 0.04,
  "verdict": "false",
  "evidence": [
    {
      "source": "Wikipedia",
      "url": "https://en.wikipedia.org/wiki/Great_Wall_of_China",
      "snippet": "The Great Wall of China cannot be seen from space with the naked eye.",
      "supports_claim": false,
      "authority_score": 0.92,
      "retrieved_at": "2025-01-22T12:00:00Z"
    },
    {
      "source": "Google Fact Check",
      "url": "https://toolbox.google.com/factcheck/explorer/...",
      "snippet": "Claim: Great Wall visible from space. Rating: False.",
      "supports_claim": false,
      "authority_score": 0.88,
      "retrieved_at": "2025-01-22T12:00:01Z"
    },
    {
      "source": "web",
      "url": "https://science.nasa.gov/great-wall-space-myth",
      "snippet": "NASA astronauts confirm the Great Wall is not visible from orbit without aid.",
      "supports_claim": false,
      "authority_score": 0.90,
      "retrieved_at": "2025-01-22T12:00:02Z"
    }
  ],
  "dimensions": {
    "source_authority": 0.90,
    "cross_reference": 0.95,
    "recency": 0.82,
    "llm_analysis": 0.97
  },
  "latency_ms": 156,
  "credits_used": 1
}

Code examples

Python

import signalstack

client = signalstack.SignalStack(api_key="ssk_live_...")

result = client.verify.claim(
    claim="The Great Wall of China is visible from space",
    sources=["web", "wikipedia", "google_fact_check"],
)

print(f"Verdict: {result.verdict}")
print(f"Trust score: {result.trust_score}")
for evidence in result.evidence:
    print(f"  {evidence.source}: {evidence.snippet}")

cURL

curl -X POST https://signal-stack-ten.vercel.app/v1/verify/claim   -H "Authorization: Bearer $SIGNALSTACK_API_KEY"   -H "Content-Type: application/json"   -d '{
    "claim": "The Great Wall of China is visible from space with the naked eye",
    "sources": ["web", "wikipedia", "google_fact_check"]
  }'

TypeScript

import { SignalStack } from "@signalstack/sdk"

const client = new SignalStack({ apiKey: process.env.SIGNALSTACK_API_KEY! })

const result = await client.verify.claim({
  claim: "The Great Wall of China is visible from space with the naked eye",
  sources: ["web", "wikipedia", "google_fact_check"],
})

console.log(`Verdict: ${result.verdict}`)
console.log(`Trust score: ${result.trustScore}`)

Next steps

Review Error Codes
Learn about Trust Scoring
Browse SDK documentation