Fact Check API

curl -X POST https://factcheck.ounie.com/api/checks \
  -H "Authorization: Bearer fct_live_…" \
  -H "Content-Type: application/json" \
  -d '{
    "claim": "The Eiffel Tower was completed in 1889.",
    "strictness": "high"
  }'

The verdict comes back on the same request — typically in 5–12 seconds, since the check runs a live search and reads the pages it finds. There is no job to poll.

Three credentials are accepted, in this order:

• Your app key — Authorization: Bearer fct_live_…, minted at /dashboard/api-keys. Up to 5 active. Only the sha256 hash is stored; the raw token is shown once.
• The fleet master key — your ounie.com developer key (ounie_live_…) works here too, once you enable “Use across Ounie apps” in your ounie.com settings.
• The shared session cookie — the dashboard uses it. Any signed-in .ounie.com browser session works.

Hosts that can't set a header (the Ounie AI Team's manual MCP entries, for one) may pass the key as ?api_key=fct_live_… on any endpoint.

{
  "ok": true,
  "check": {
    "id": "…",
    "claim": "The Eiffel Tower was completed in 1889.",
    "strictness": "high",
    "status": "succeeded",
    "verdict": "supported",
    "confidence": 1,
    "reasoning": "Multiple independent sources confirm…",
    "evidence": [
      {
        "stance": "supports",
        "quote": "On March 31, 1889, the Eiffel Tower is dedicated in Paris…",
        "url": "https://www.history.com/this-day-in-history/march-31/eiffel-tower-opens",
        "title": "Eiffel Tower opens in Paris | March 31, 1889",
        "publishedAt": "2009-11-24"
      }
    ],
    "sources_searched": 11,
    "domains_cited": 3,
    "thin": false,
    "credits_spent": 8
  }
}

quote is verbatim from the page and url is a page we actually fetched — those two together are the contract. Evidence citing a URL the adjudicator was not shown is dropped before it reaches you, and title and publishedAt are filled in from our record of the page rather than from the model, so a real quote can never appear beside an invented date.

sources_searched is how many candidate pages the search returned; domains_cited is how many independent publishers survived into the evidence. When the two diverge sharply, the claim is popular but poorly sourced — which is worth knowing.

With strictness: "high", supported and contradicted require agreeing evidence from at least two independent registrable domains. Fall short and the verdict degrades to mixed, with downgraded_from naming what it would otherwise have been. Two pages on one site count once.

One rule applies at every strictness: a decisive verdict with no agreeing evidence at all is never returned. It degrades regardless of what you asked for.

A thin result is an unverifiable verdict with zero surviving evidence: we looked and there is nothing to show you. It is a non-answer, so it is never billed.

• Credit rails (REST, MCP) — the full reserve is refunded pool for pool and no ledger entry is written. credits_spent is 0.
• x402 — the payment is never settled. Verification happens before the check runs and settlement only after there is a verdict, because an on-chain settlement is final and there is no refund path. You get a 402 thin_result.

Free, forever — reading work you already paid for never costs anything.

GET /api/checks?limit=20&verdict=contradicted
GET /api/checks/<id>
GET /api/credits          # your spendable balance
GET /api/pricing          # public: price, verdicts, x402 terms

A Streamable-HTTP MCP server, plus legacy SSE. Works with Claude, Cursor, ChatGPT, the AI SDK and the Ounie AI Team.

Endpoint  https://factcheck.ounie.com/api/mcp   (legacy SSE: /api/sse)
Auth      Authorization: Bearer fct_live_…

# For hosts that can't set static headers (Ounie AI Team):
https://factcheck.ounie.com/api/mcp?api_key=fct_live_…

For agents with no Ounie account. USDC on Base; the 402 quotes the terms, you sign and retry.

curl -X POST https://factcheck.ounie.com/api/x402/check \
  -H "Content-Type: application/json" \
  -d '{"claim":"…","strictness":"high"}'

# → 402
{ "x402Version": 1,
  "accepts": [{ "scheme": "exact",
                "network": "base",
                "maxAmountRequired": "96000",
                "payTo": "0x…",
                "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913" }] }

curl -X POST https://factcheck.ounie.com/api/x402/check \
  -H "X-Payment: <base64 signed payload>" \
  -H "Content-Type: application/json" \
  -d '{"claim":"…","strictness":"high"}'

$0.096 per claim. The order is verify → check → settle: your signature is checked off-chain first (so a bad header cannot burn search budget), the check runs, and money only moves once there is a verdict with evidence to hand back.

Credits are shared across every Ounie app and bought at ounie.com. There is no subscription here and no per-app balance.