Vitals Rail

Estimate Core Web Vitals-style metrics (LCP, CLS, resources) on the active page.

Vitals Rail shows a quick performance snapshot for the page you are viewing. How it works: • Open a normal http or https page and let it load • Click the extension icon and tap Measure page • Review estimates such as LCP, FCP, CLS, TTFB, resource count, and DOM ready time Details: • Values come from browser Performance APIs when available • Results are advisory estimates — not a full lab/field audit • Handy for quick checks during development and QA • Works only on regular websites — not on chrome:// pages • No account and no cloud sync Privacy: • Metrics are read only in your browser • Nothing is uploaded to a server • Works offline after install (for already loaded pages)