Independent verification · pay per claim
Fact Check is a second opinion your agent can call. Post one claim and get back a verdict — supported, contradicted, mixed or unverifiable — with the quoted evidence and live URLs that produced it.
The four verdicts
A checker that can only say yes or no will say yes or no to anything. These four are the whole vocabulary — and the last two are the ones that keep the first two worth something.
How a check runs
One assertion, stated plainly. Add context if it matters — who said it, where, what it was answering.
Two query angles run at once: sources that would establish the claim, and sources that would refute it. Asking only the first is how a checker ends up agreeing with everything.
Every verdict arrives attached to the quotes and live URLs that produced it. A citation the adjudicator could not have read is dropped, never repaired.
Evidence anatomy
Every item in the evidence array carries four fields, and all four come back on the wire. You can open the URL and find the quote.
If the adjudicator produces a citation pointing at a page it was never shown, that citation is deleted before you ever see it — and if deleting it leaves nothing behind, the verdict collapses to unverifiable and you are not charged. A fabricated source is the one failure this product is built to make impossible.
One source speaks to it.
Strictness
Send strictness: "high" and a decisive verdict needs agreement from two independent domains. Fall short and the answer degrades to mixed — honest about what the sources actually establish.
Two pages on the same site do not count twice, because a publisher quoting itself is still one publisher. Use high strictness before you publish; normal when you just want a read.
For developers & AI agents
Three rails, one meter. Every call refuses rather than overdraws: an agent that runs out of credits gets a 402 with the exact shortfall and a link to top up, never a silent debt.
Bearer key or the shared Ounie session cookie. Synchronous — the verdict comes back on the same request.
curl -X POST https://factcheck.ounie.com/api/checks \
-H "Authorization: Bearer fct_live_…" \
-H "Content-Type: application/json" \
-d '{"claim":"The filing deadline moved to April 30.",
"strictness":"high","recency_days":180}'check_claim, get_check, list_checks, get_verdict_taxonomy, get_credit_balance, get_pricing, whoami. Works in Claude, Cursor, ChatGPT and the Ounie AI Team — that last one can't set headers, so the key rides the URL.
Endpoint https://factcheck.ounie.com/api/mcp (legacy SSE: /api/sse)
Auth Authorization: Bearer fct_live_…
# Hosts that can't set headers (e.g. the Ounie AI Team):
https://factcheck.ounie.com/api/mcp?api_key=fct_live_…Keyless agents pay on Base. The 402 quotes the terms; sign and retry. Verification happens BEFORE settlement, so a claim with no evidence never takes your money — there is no refund on chain, so the check has to come first.
curl -X POST https://factcheck.ounie.com/api/x402/check \
-H "Content-Type: application/json" \
-d '{"claim":"…"}'
# → 402 { accepts: [{ scheme:"exact", network:"base",
# maxAmountRequired:"96000", payTo:"0x…" }] }
curl -X POST https://factcheck.ounie.com/api/x402/check \
-H "X-Payment: <base64 signed payload>" -d '{"claim":"…"}'8 credits per claim on the credit rails · $0.096 per claim on x402 · the dashboard shows every check you have run, free to re-read.
Credit math
One credit is one cent, drawn from the same Ounie wallet as every other Ounie app. Credits are reserved when the check starts and settle only when there is a verdict with evidence behind it.
8 credits reserved while the check runs.
Questions
A model answering from memory is exactly the thing you are trying to check. Fact Check searches live sources first, then adjudicates only from what it retrieved, and drops any citation pointing at a page it was not shown. The verdict is a function of the evidence attached to it — you can open every URL yourself.
Two gates. Every evidence item must carry a verbatim quote and a URL, and that URL must match a page we actually fetched — anything else is deleted before you see it. And a verdict left with no surviving evidence collapses to unverifiable and is refunded, so fabricating a citation earns the model nothing.
That nothing published settles the claim either way. It comes in two flavours, and only one of them is free. If we searched and found nothing at all to weigh, that is a non-answer and costs you nothing. If we did surface coverage and none of it establishes the claim, that is a real finding — you get the sources we weighed, and it bills normally.
Before anything goes out under your name. High strictness will not return supported or contradicted unless two independent publishers agree; a single source degrades to mixed. Use normal when you want a fast read and can live with one strong source.
8 Ounie credits per claim — 0.08 in plain money, from the same wallet as every other Ounie app. No subscription, no minimum. Reading, listing and exporting checks you already paid for is free forever.
Yes. The x402 endpoint takes USDC on Base with no account and no key. It verifies your signature, runs the check, and only settles once there is a verdict with evidence to hand back — an on-chain settlement is final, so a thin result is refused before the money moves rather than refunded after.
Checks you run while signed in are saved to your dashboard so you can re-read and cite them later, and you can delete your account data by contacting us. x402 checks are stored without an owner, since a keyless caller has no account to attach them to.
Yes — pass recency_days to restrict the evidence to a recent window. That is the right setting for claims about current state (prices, availability, who holds an office) where an old but well-sourced page would give you a confidently wrong answer.
Sign in with the Ounie account you already have. Your first check costs 8 credits — and nothing at all if there is no evidence to hand you.