Core Web Vitals measure real-world loading performance, responsiveness, and visual stability. The current metrics are Largest Contentful Paint, Interaction to Next Paint, and Cumulative Layout Shift.
Google considers Core Web Vitals as part of page experience alongside many other signals. They are useful because the underlying problems are also visible to people: slow main content, delayed interactions, and layouts that move while someone is trying to tap.
PageSpeed Insights may show Chrome field data and a separate Lighthouse lab test. The 0–100 Lighthouse performance score is useful for diagnosis, but it is not itself a Core Web Vitals report card.
Run a page through PageSpeed Insights. Check whether field data is available, review each Core Web Vital, then use the Lighthouse diagnostics to investigate likely causes.
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This is part of the custom web design work.