Frontend Performance (Part 2): Core Web Vitals — LCP, INP, CLS

Core Web Vitals (LCP, INP, CLS) measure loading, interactivity, and visual stability. They affect user experience and search ranking. This post explains what each metric means, how to improve them, and how to monitor and set budgets as a senior frontend.

LCP (Largest Contentful Paint)

LCP measures when the largest visible content element (image, video, or text block) is painted. It reflects how quickly the main content appears. Good: under 2.5 seconds. Poor: over 4 seconds.