How to fix cwv cls on Shopify Plus

Steps for Shopify Plus

1. All standard Shopify steps above apply. Additionally, use Shopify Scripts or Launchpad to ensure promotional banners and flash-sale bars are pre-rendered in theme sections rather than injected via client-side JavaScript.
2. For checkout extensions: in the Shopify Plus Checkout Editor, all blocks are rendered server-side with reserved space — avoid injecting custom checkout content via external scripts that fire after load.
3. Use Shopify's CDN image transformations ({{ image | image_url: width: 800 }}) and always pair with width/height attributes in Liquid to prevent CLS on checkout and account pages.

What is cwv cls?

Cumulative Layout Shift (CLS) measures how much page content unexpectedly moves around while a visitor is looking at it. Every time an image pops in and shoves text down, a banner slides in from a cookie notice, or a font swap causes a paragraph to reflow, that counts as a layout shift. Google adds all those shifts together into a single score; anything above 0.1 is considered "needs improvement," and above 0.25 is "poor." A score of 1.35 (like the example above) means the page is shifting dramatically — visitors are misclicking, losing their place, and bouncing before they buy.

CLS is one of Google's three Core Web Vitals and is a direct ranking signal in Google Search — a poor score actively suppresses your position in search results, reducing organic traffic and revenue. On mobile, where most ecommerce shopping happens, layout shifts are especially jarring: a customer tapping "Add to Cart" can accidentally tap a shifted link instead, killing the conversion. High CLS also signals a low-quality page experience, which increases bounce rate and reduces the trust visitors place in your store. Google's own data shows that sites meeting Core Web Vitals thresholds see measurably better business outcomes than those that don't.

See the complete Cwv cls guide for every platform and the full background.