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How to use Core Web Vitals?

Read the real-world performance report for your store and understand what CLS, LCP and INP mean.

Written by Arsalan Ali

The Core Web Vitals report displays real-world user experience data for your store's performance. Unlike a one-off speed test, it is built from what actual visitors experienced on your site over the last 28 days — which is exactly the data Google uses when it judges page experience.

Core Web Vitals Assessment in AI SEO App with Cumulative Layout Shift, Largest Contentful Paint and Interaction to Next Paint cards

Open the report

  • In your Shopify admin, go to Apps → AI SEO App.

  • Select Core Web Vitals in the app menu.

Each metric is shown as a card with your current value, a plain-English explanation, and the Good / Moderate / Poor thresholds so you can see where you stand at a glance. The data is sourced from real-time PageSpeed data.

Cumulative Layout Shift (CLS)

Measures how much your page content moves around while it loads. A high CLS is what makes a shopper tap the wrong button because the layout jumped underneath their finger.

  • Good: 0 – 0.1

  • Moderate: 0.1 – 0.25

  • Poor: above 0.25

Usual causes: images and embeds without set dimensions, banners injected above existing content, and web fonts that swap late.

Largest Contentful Paint (LCP)

Measures how long it takes for the main content of the page — usually your hero image or product photo — to appear.

  • Good: 0 – 2.5 seconds

  • Moderate: 2.5 – 4 seconds

  • Poor: over 4 seconds

Usual causes: heavy uncompressed images, slow server response, and render-blocking CSS or JavaScript. Image Optimization and Preload Key Theme Assets both help here.

Interaction to Next Paint (INP)

Measures how quickly your page responds when a shopper taps or clicks something.

  • Good: under 200 ms

  • Moderate: 200 – 500 ms

  • Poor: over 500 ms

Usual causes: too many apps and scripts competing for the browser's attention. Removing apps you no longer use is often the single most effective fix.

How to improve your scores

  • Run Image Optimization to cut down page weight — this most often improves LCP.

  • Enable Preload Key Theme Assets so essential JS, CSS and font files load sooner.

  • Enable Instant Click so navigation between pages feels immediate.

  • Remove unused apps and third-party scripts from your theme.

Core Web Vitals are based on a rolling 28-day window, so give your changes a couple of weeks before judging the effect.

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