A user modified their store’s source files and achieved a strong desktop performance score on Google Lighthouse, but the mobile score remained significantly lower.
Key Issue:
Changes made to improve speed only affected desktop, not mobile
Two screenshots were shared showing the performance discrepancy between platforms
Suggested Solution:
Follow the mobile-specific recommendations provided by Lighthouse
Shopify allows uploading different images for mobile vs. desktop—ensure optimizations target both platforms separately
Implementing mobile-focused suggestions should improve the mobile speed score
Status: The question remains open with one response offering guidance but no confirmed resolution yet.
Summarized with AI on November 15.
AI used: claude-sonnet-4-5-20250929.
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?
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.