How do I fix Core Web Vitals on Shopify?

What to do about it

1. Open Settings, then Apps and sales channels, and uninstall apps you do not use. Apps can inject scripts into your theme; check the theme code editor for leftover snippets after removing one.
2. Upload product photos at a consistent, reasonable size. Shopify’s CDN serves scaled, modern-format versions automatically, but consistent source images make pages predictable.
3. Keep your theme current (Online Store, then Themes). Newer themes are built with performance in mind; a heavily customized old theme is a common source of slow pages.
4. Limit hero videos, stacked sections, and slideshows on the homepage. Each one adds weight and layout risk.
5. Remember the limit: hosting and the checkout belong to Shopify. If server response is the problem, the levers left to you are apps, theme, images, and sections.

What WebVitalist checks

The free scan runs 19 technical checks on one public URL. These are the ones that matter for this question:

• HTML size (html-size): The free scan warns when the HTML document is larger than 400 kB, which the browser must download and parse before it can paint anything.
• Server response time (ttfb): Shopify controls the hosting, so you cannot change the server. The free scan still records server response time, so you know whether delivery or page weight is your problem.

A paid audit ($9 and up) also runs a real mobile Lighthouse test through Google PageSpeed Insights and reads field data for LCP, INP and CLS, where Google has it.