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Debugging: your site works, but does it really perform well?

Chrome DevTools, Core Web Vitals, and Lighthouse help identify slowdowns and layout shifts and improve the user experience.

A website can work perfectly… and still offer a poor user experience.

An image that appears too late, a button that responds slowly, content that shifts while loading: these small details can quickly become frustrating.

Fortunately, Chrome DevTools lets you see what is really happening behind the screen.

Three metrics deserve particular attention:

  • CLS - Does content move during loading or use?
  • LCP - Does the main content appear quickly?
  • INP - Does the site respond quickly to interactions?

The Performance tab lets you analyze these metrics and identify the elements causing slowdowns or layout shifts.

Lighthouse can provide an initial assessment of performance, accessibility, and SEO.

An error-free site is not necessarily a fast, responsive site.

Debugging should therefore not be reserved for moments when something stops working. It is also a habit to develop throughout the development process.

Do you check Core Web Vitals during development?