Understanding and Optimizing Google's Core Web Vitals: LCP, CLS, and INP

Google's Core Web Vitals are a set of user experience metrics that measure how users perceive the loading and interactivity of a page. Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and First Input Delay (FID) are the main ones. They're essential for page experience ranking and will become a ranking factor in June 2021. Here's how to analyze and improve them.

Google's new ranking factor, Page Experience, will combine Core Web Vitals and other signals. It's based on real-world data from Chrome User Experience Report (CrUX). The Core Web Vitals metrics will be scored on a scale from 0 to 100. Scores below 4 on any will harm search rankings.

LCP is the time from when a page's content starts rendering to when a user's largest text block or image is painted. It's a user-centric metric. It's the time from navigation to the first meaningful paint, excluding web fonts and placeholders. The LCP threshold is 2.5 seconds.

To improve LCP, compress images, defer JavaScript, and lazy-load non-critical resources. Use web.dev/measure-lcp to test and optimize.

Avoid layout shifts by sizing content and reserving space for ads and web fonts. Defer offscreen images and web fonts. Minimize main-thread work and third-party requests. Use the `intersectionObserver()` API for lazy-loading.

CLS is the summed distance images and ads move the user's expected layout. It's the largest shift in pixels. The CLS threshold is 0.150px. Use `position: sticky` and `transform` to fix elements. Remove layout shifts in third-party embeds.

FID is the time from user input to the browser's response. It's the total blocking time. Reduce JavaScript and render-blocking resources. Use `requestIdleCallback()` for deferred tasks.

Use a critical path strategy. Minimize HTTP requests and compress critical CSS. Avoid blocking resources. Use a service worker for caching and background preloading.

Optimize your server response time and TTFB. Use a CDN, Gzip, and Brotli. Use `preconnect` and `dns-prefetch`. Avoid redirects and render-blocking resources. Use `rel="preload" as` and `preconnect` for fonts.

Use `rel="preload as"` for critical CSS and JavaScript. Use `async` for non-critical resources. Avoid `async` and defer parsing. Use `async` for critical JavaScript.

Avoid `document.write()` and `eval()`. Use `requestAnimationFrame()` for animations. Optimize `setTimeout()`. Use `requestIdleCallback()` and `IntersectionObserver()`. Minimize server round-trips.

Avoid `console.log()` and `alert()`. Minimize `console.error()` and `console.warn()`. Use `console.info()` and `console.debug()`. Avoid `console.dir()` and `console.dirxml()`.

Use `console.trace()` for debugging. Minimize console logs in production. Avoid `console.group()` and `console.groupCollapsed()`. Use `console.count()` for logging. Use `console.time()` and `console.timeEnd()`.

Optimize resource loading. Use `rel="dns-prefetch" and `dns-prefetch`. Use `preload` for critical resources. Avoid `preload` for non-critical resources.

Avoid `setTimeout()` and `setInterval()`. Use `requestIdleCallback()` and `setImmediate()`. Use `requestIdleCallback()` for defer tasks.

Use `Promise.allSettled()`. Minimize `setImmediate()` and `setTimeout()`. Avoid `setTimeout()` for deferred tasks.

Use `Promise.race()` for async tasks. Use `requestIdleCallback()` for async tasks. Avoid `setTimeout()` for defer tasks.

Optimize critical resources. Use `IntersectionObserver()` and `Element.getBoundingClientRect()`. Avoid `setTimeout()` for defer tasks.

Use `requestAnimationFrame()` for animations. Avoid `setTimeout()` for defer tasks. Use `requestAnimationFrame()` for async tasks.

Use `requestIdleCallback()` for defer tasks. Avoid `setTimeout()` for deferred tasks.

Use `MutationObserver()` and `Element.getBoundingClientRect()`. Avoid `setTimeout()` for defer tasks.

Optimize critical resources. Use `requestIdleCallback()` for defer tasks. Avoid `setTimeout()` for deferred tasks.

Use `requestAnimationFrame()` for animations. Avoid `setTimeout()` for deferred tasks.

Optimize critical resources. Use `requestAnimationFrame()` for async tasks. Avoid `setTimeout()` for deferred tasks.

Avoid `setTimeout()` for

Conclusion: briefly recap the key actions and remind about the importance of consistency.