AudityxeAudityxe

Audit module

Core Web Vitals & Performance Audit

How does Audityxe measure Core Web Vitals?

Audityxe reports Core Web Vitals through Google's PageSpeed Insights (a real-browser Lighthouse run) and the Chrome UX Report (real-user data) — on the Pro plan in the web app, or in the free CLI when you supply your own PageSpeed Insights API key with --psi-key.

Without PageSpeed Insights, Audityxe still audits the performance signals visible in the HTTP response and HTML. It does not run a browser itself, so JavaScript-rendered metrics come only from the PageSpeed/CrUX modules.

Real-browser PageSpeed Insights is a Pro-plan feature on the website. In the CLI it is free, using your own Google API key.

What is checked

Lighthouse Audit (via PageSpeed Insights)

A real-browser Lighthouse pass run by Google.

  • LCP (Largest Contentful Paint)
  • CLS (Cumulative Layout Shift)
  • TBT (Total Blocking Time)
  • FCP (First Contentful Paint)
  • Speed Index
  • Lighthouse Performance, Accessibility, Best Practices, and SEO category scores

Real-User Experience (CrUX)

Aggregated 28-day Core Web Vitals from real Chrome users, when Google publishes data for the site.

  • 75th-percentile real-user values with good / needs-improvement / poor verdicts
  • Clear "no data" reporting for low-traffic sites

Performance

Signals measurable without a browser.

  • Server response time
  • HTML document size
  • Render-blocking stylesheets
  • External scripts
  • Lazy-loaded images
  • Redirect chain
  • Response compression
  • Sampled image weight and asset payload distribution
  • Layout-shift risk from embeds

TTFB (Time to First Byte)

Server responsiveness.

  • Time to First Byte
  • Redirect overhead on TTFB
  • Server-side compression

Image Optimization & Third-Party Scripts

Common causes of slow pages.

  • Explicit image dimensions
  • Modern image formats
  • Lazy loading
  • Inline base64 images
  • Analytics, ad, tag-manager, chat, and web-font third parties

How to run it

Web app: Pro plan: run an audit and enable the PageSpeed option.

Command line (see the CLI guide):

npx audityxe-cli https://example.com --psi-key YOUR_GOOGLE_KEY

Frequently asked questions

Does Audityxe measure LCP and CLS?

Yes, when the Lighthouse pass is enabled (Pro plan on the website, or --psi-key in the CLI). Audityxe reports LCP, CLS, TBT, FCP, and Speed Index with good, needs-improvement, or poor verdicts.

Does Audityxe analyze JavaScript bundle size or detect memory leaks?

No. Audityxe does not include a bundle analyzer or memory-leak detection. Its performance checks cover server response, document and asset weight, compression, render-blocking resources, and the PageSpeed Lighthouse metrics.

Why does Audityxe say there is no real-user data for my site?

Google only publishes Chrome UX Report data for sites with enough real Chrome traffic. New or low-traffic sites commonly have none; that is informational, not a problem with the site.

Last reviewed against the Audityxe source code. Product names mentioned are trademarks of their respective owners; Audityxe is not affiliated with them.