Core Web Vitals

Core Web Vitals are a set of user-centered metrics introduced by Google to measure key aspects of web experience: loading performance (Largest Contentful Paint - LCP), interactivity (First Input Delay - FID, soon replaced by Interaction to Next Paint - INP), and visual stability (Cumulative Layout Shift - CLS). As of 2024, INP has replaced FID as the responsiveness metric. Good thresholds: LCP ≤ 2.5s, INP ≤ 200ms, CLS ≤ 0.1. These metrics are part of Google’s Page Experience signals and influence ranking, especially on mobile. Tools like PageSpeed Insights, Lighthouse, and Chrome UX Report help measure and optimize them.