Core Web Vitals Monitoring

An important, user-centric metric for measuring visual stability because it helps quantify how often users experience unexpected layout shifts — a low CLS helps ensure that the page is delightful.

An important, user-centric metric for measuring load responsiveness because it quantifies the experience users feel when trying to interact with unresponsive pages — a low FID helps ensure that the page is usable.

The Largest Contentful Paint (LCP) metric reports the render time of the largest image or text block visible within the viewport, relative to when the page first started loading. To provide a good user experience, sites should strive to have Largest Contentful Paint of 2.5 seconds or less. To ensure you're hitting this target for most of your users, a good threshold to measure is the 75th percentile of page loads, segmented across mobile and desktop devices.

The First Contentful Paint (FCP) metric measures the time from when the page starts loading to when any part of the page's content is rendered on the screen. For this metric, "content" refers to text, images (including background images), svg elements, or non-white canvas elements. To provide a good user experience, sites should strive to have a First Contentful Paint of 1.8 seconds or less. To ensure you're hitting this target for most of your users, a good threshold to measure is the 75th percentile of page loads, segmented across mobile and desktop devices.