FactLens - Math & Claim Fact Checker

Audit highlighted numbers, percentages, and empirical claims on any webpage with Gemini.

Verify numbers, percentages, and financial statistics as you read. FactLens inspects highlighted claims and runs an independent mathematical verification check directly in your browser. Whether you are reading financial filings, news articles, blog posts, or research briefs, FactLens catches inconsistent numbers and faulty arithmetic in seconds. HOW IT WORKS 1. Highlight any sentence or paragraph containing quantitative data on any web page. 2. Click the FactLens icon in your extension toolbar. 3. Review an instant structured verification card detailing: • Status Badge: PASS, FAIL, or INCONCLUSIVE • Extracted Claim: The exact assertion being tested • Step-by-Step Calculation: Explicit arithmetic breakdown • Explanation: Plain-English summary of whether the numbers reconcile KEY FEATURES • Zero-Latency Extraction: Automatically pulls your current selection when opened. • Deterministic Linter: Uses structured output schemas—not conversational chatter. • Bring Your Own Key (BYOK): Uses your own Google Gemini API key. Your data communicates directly with Google's API endpoint—no third-party proxy servers or analytics tracking. • Completely Free: No subscriptions, no credit cards, and no usage tiers. PRIVACY & PERMISSIONS FactLens requests only the permissions necessary to inspect selected text (`activeTab`, `scripting`, `storage`). Your API key is encrypted and stored locally in your browser (`chrome.storage.local`).