Definition of Core Web Vitals
Core Web Vitals are three key metrics (CLS, FID, and LCP) that measure how real-world users experience the performance and usability of your website. They're designed to help developers and site owners prioritize improvements that impact user experience the most.
Core Web Vitals are like the three-card poker of web performance: simple to understand, easy to measure, and — if you’re good — highly profitable to monitor. They’re distilled from dozens of meaningful metrics into three categories that represent the most common issues users face when interacting with a site.
Google uses Core Web Vitals as ranking signals because they’re correlated with user engagement and retention. When you fix these, your users stay longer, buy more, and enjoy their experience.
Core Web Vitals as Part of an Observability Practice
Monitoring Core Web Vitals is table stakes for any serious performance and usability observability practice. These metrics help you see how your site performs in the real world — across devices, networks, and usage patterns — and guide you toward meaningful improvements that matter to your users.