Real-time fact checking

Know what's true, as you read.

A browser extension that checks whether claims are accurate in real time, using live web search. Verify text, video audio, and files, right where you find them.

Sign in with your email and try it free. Upgrade with your own API key for unlimited checks.

One extension, six ways to check

From a highlighted text to a whole video, get a grounded verdict with sources.

Text and Pages

Highlight any text or scan a full article. Claims are verified with web search and rated on a true to false scale.

Live Video Audio

Fact-check a YouTube or any video tab while it plays. The audio is transcribed and spoken claims are checked as they happen.

Documents and Images

Upload a PDF, image, or text file to check the claims inside it, or ask follow-up questions grounded in exactly what the file says.

Sentiment Analysis

Paste comments, tweets, or reviews to read the overall mood, the positive to negative split, and the themes driving it.

AI Detector

Check whether an image or document was made by AI, using verifiable Content Credentials where present, with an honest likelihood otherwise.

Corrections and Follow-ups

False claims come with the accurate fact, and you can ask follow-up questions about any result right on the card.

How LitmusAI compares?

Three different tools for trusting what you read. Here's what each one actually checks.

Capability LitmusAI NewsGuard Ground News
Highlight and Check Facts
Live Video Audio
Files Upload
Sentiment Analysis
AI Content Detector
Cited Sources
Bring Your Own API Key
Corrections on Flagged Claims
Free Tier

Based on each product's public listing at the time of writing. They stack, not compete, a reliable outlet can still publish one false claim.

Simple plans that scale with you

Start free. Upgrade with your own API key for unlimited checks and more features.

Free
$0
5 checks total, free for life
  • Highlight to Fact-Check
  • Web-grounded verdicts with sources
  • Scan Page
  • Document & Image Check
  • Sentiment Analysis
  • AI Detector
  • Live Audio Fact-Check
Start free
Max
$12/ month
Everything in Pro, plus live audio
  • Everything in Pro
  • Live Audio Fact-Check, 30 min/day
Get Max

Install the extension, sign in, then choose your plan. Pro and Max run on your own API key, added right in the extension. Cancel anytime. Payments handled securely by Stripe.

Private by design

Your check history lives only in your browser. Content you check is used only to return your result, forwarded to the AI providers that power the checks (Anthropic, OpenAI, Google Gemini, or Perplexity, depending on your setup, and Deepgram for audio). We never sell it, and there is no ad tracking. See the privacy policy for the full picture.

Frequently asked questions!

What people ask before installing LitmusAI?

How does LitmusAI check a claim?

Start a check any of these ways:

  • Highlight a piece of text on any page
  • Scan a whole page or article
  • Upload a file, like a PDF or image

LitmusAI then searches the live web for sources related to the claim and shows you a verdict, ranging from true to false, along with the sources it used.

Is LitmusAI free?

Yes. The Free plan gives you:

  • 5 checks total, free for life
  • Highlight-to-check on any page

If you check things often, Pro and Max remove that limit and add more features on top, like page scanning, document checks, and sentiment analysis.

What's the difference between Pro and Max?

Pro is built for everyday fact-checking, with no daily limit:

  • Highlight-to-check on any page
  • Full page scans
  • Document and image checks
  • Sentiment analysis
  • AI content detection

Max includes everything in Pro, plus:

  • Live audio fact-checking, so you can check claims spoken in a video or call as they happen
Do I need my own API key?

Free works right out of the box, no key needed. Pro and Max ask you to add your own API key inside the extension after you sign in. This means:

  • Your checks run directly through the AI provider, at their normal cost
  • You're not paying a marked-up subscription price for the same usage
Is my data private?
  • Your check history is stored only in your own browser, not on our servers
  • Content you check is sent only to the AI provider needed to return your result
  • We never sell your data or use it for ad tracking

Read the full privacy policy for the complete picture.

Can I cancel anytime?
  • Yes, cancel your Pro or Max plan whenever you want, no lock-in or long-term contract
  • Payments are handled securely by Stripe, so your card details never pass through LitmusAI directly