What are Core Web Vitals?

Why it matters

Core Web Vitals matter for two reasons at once. Google uses them as a ranking signal, so a sluggish page can quietly cost you positions in search. And separately, they track the things that make visitors leave: a page that takes too long to show up, a button that does nothing when tapped, a layout that jumps as it loads. Faster, steadier pages keep more people around and convert better, which is the part that actually pays the bills.

The three you measure

There are three. LCP, or Largest Contentful Paint, is how long until the main content is visible, ideally under 2.5 seconds. INP, or Interaction to Next Paint, is how quickly the page reacts when someone taps or clicks. CLS, or Cumulative Layout Shift, is how much the page jumps around while it loads. Each has a clear pass or fail threshold, measured on real visitors rather than a lab machine.

How we approach it

We treat these as a build constraint, not a cleanup task. A fast site is something you design in: trimming what the browser has to download, reserving space so nothing jumps, and rendering on the server where it helps. It is the same discipline behind any well-built web app, and it is why our work passes these checks by default instead of needing a rescue later.