Store speed test issue in mobile

Shopify Partner
74 0 7

Hello, i made some changes in the source files and i ran a speed test using the Google Lighthouse but i noticed that in the desktop the score is great but the same thing didn't happed and in mobile. Does anyone knows why this happed?


Thanks in advance!


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Replies 2 (2)
Shopify Partner
25 1 1

Hello Mpatsia,

You have to follow the suggestions which are given to you for mobile. Shopify does have a section to upload different images for mobile and desktop, so it might have happened that the changes you made only affected desktop and not mobile. If you follow suggestions for mobile, it will definitely improve speed for mobile.

If you find my suggestion difficult to implement send an email at 

23 3 4


There are a few reasons why your Google Lighthouse score for mobile may be lower than your score for desktop, even after making changes to your source files.

  • Mobile devices have less powerful processors and slower network connections than desktop computers. This means that it can take longer for a mobile device to load and render web pages.
  • Mobile browsers have to render pages in different ways than desktop browsers. For example, mobile browsers may have to resize images or adjust CSS rules to fit the smaller screen size.
  • Mobile users are more likely to be using a cellular network connection, which is typically slower than a Wi-Fi connection. This can also impact page loading times.

    Here are a few things you can do to improve your mobile Lighthouse score:
  • Optimize your images for mobile devices. Make sure to resize your images appropriately for mobile screens and use efficient image formats such as WebP.
  • Minimize your use of JavaScript and CSS. The more JavaScript and CSS you have on your page, the longer it will take to load.
  • Use a content delivery network (CDN) to serve your static assets. This will help to reduce the load time for users who are located far away from your server.
  • Use a caching plugin to store static copies of your pages on your users' devices. This will allow your pages to load faster on subsequent visits.

    Here are some specific things to check for in your source files that may be causing your mobile Lighthouse score to be lower than your desktop score:
  • Large or unoptimized images.
  • Unused JavaScript or CSS.
  • Third-party libraries that are not optimized for mobile devices.
  • Render-blocking resources.
  • Long main thread tasks.

    You can use the Lighthouse report to identify specific areas where you can improve your mobile score. The report will provide you with a list of recommendations, along with links to additional resources.

Even by making small changes to your source files, you can significantly improve your mobile Lighthouse score. This will help to improve the user experience for your mobile visitors.

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