The fact-checking tool for professional reviewers and editors.
Paste a claim, get a sourced verdict: True, Mostly True, Misleading, or False, with a 1–10 score, cited sources graded for authority, and the full reasoning behind the call. Built for the people whose name goes on the published piece.
Work claim by claim in the Workbench, or automate the volume through the API — same pipeline, same evidence, same record.
Two ways to work.
Hands-on review or automated pipeline — the same verification underneath.
The Workbench
- Submit several claims at once and review the verdicts as they land
- Full evidence per verdict: cited sources, the debate, the reviewers' reasoning
- Your library keeps every checked claim; watch a claim for verdict changes and new evidence
Desktop browser. Free account, no card required.
The API
- Extract claims from whole documents and verify them in bulk
- Wire fact-checking into the publishing pipeline — auto-approve or flag for review
- Python and TypeScript SDKs, webhooks, full audit trail per verdict
A verdict you can defend.
Every check runs a structured process modeled on evidence-based procedure: the claim is framed neutrally, researched across independent sources graded for authority, argued by AI models taking opposing sides, and adjudicated by three independent reviewers. You don't just get the answer — you get the case for it.
That's the difference between citing a verdict and defending one.
What a finished check looks like.
A real claim from the public library — open it to see exactly what a reviewer sees.
“Albert Einstein won the 1921 Nobel Prize in Physics for his theory of general relativity.”
Widely repeated, confidently wrong: the 1921 Nobel was awarded for the photoelectric effect. The verdict page shows the sources, the opposing arguments, and the reviewers' reasoning in full.
Open the full verification →Pricing
Start free, no card required.
Free
$0
10 deep verifications/mo
100 fast checks/mo
Full evidence on every verdict
Check your next piece today.
Pro
$99/mo
500 deep verifications/mo
5,000 fast checks/mo
1,000 follow-up questions/mo
Self-serve. $999/yr annual.
Frequently asked questions
Editorial fact-checkers publish rulings on stories their staff chose to cover. Lenz is a tool: you submit the exact claim you're checking and get a fresh, sourced verdict on it — with the research, debate, and reasoning attached. It checks your claims, not someone else's editorial calendar.
Each claim is researched across real independent sources graded for authority, argued by AI models taking opposing sides, and adjudicated by three independent reviewers. The verdict ships with citations and the full reasoning trail — you can verify the verification.
Accounts are individual today — each reviewer signs up and works in their own Workbench with their own library. For shared automated workflows, the API is the multi-seat path.
The free tier includes 10 deep verifications per month, no card required. Pro is $99/month with 500 deep verifications, 5,000 fast checks, and follow-up Q&A.
Yes — the public library holds thousands of completed verifications. Open any of them to see the verdict, sources, debate, and reasoning exactly as a reviewer would.
By use case
Check the next claim with evidence behind you.
Free account, no card required.