What is CLS by data save mode
CLS by data save mode shows Cumulative Layout Shift (CLS) segmented by whether a user had Data Saver mode enabled in their browser or device settings.
This lens helps you identify if users with data-saving preferences are more likely to experience layout shifts — often due to deferred assets, script limitations, or fallback rendering logic.
Healthy CLS by data save mode sample
In a healthy setup:
CLS is low across both enabled and disabled Data Saver sessions
Users with Data Saver don’t suffer layout instability, even if enhancements are stripped down
Visual layout remains consistent regardless of what is or isn’t loaded
This reflects strong resilience in your layout and shows that your site gracefully degrades when optimizations or scripts are unavailable.
Unhealthy CLS by data save mode sample
When CLS is high for Data Saver enabled users, it may be due to:
Missing fonts, images, or UI elements that collapse or shift during load
Critical layout shifts caused by unreliable script loading
Late-injected content replacing placeholders unpredictably
CSS or layout dependencies not loading properly in lightweight mode
This leads to a jumpy, frustrating experience for privacy-conscious, mobile-first, or budget-minded users — a segment you don’t want to lose.
Resolving unhealthy CLS by data save mode
Go-to action plan to resolve an unhealthy CLS by data save mode:
Ask Uxi to analyze your CLS by data save mode values and suggest improvements
Use Filters to isolate enabled sessions and cross-reference with connection speed, device type, or component behavior.
Simulate CLS of the suspected lens to see if fixing it will resolve the CLS by data save mode. If yes, this is where the resolution focus should be.
Use an automated CLS optimization tool like Navigation AI to improve your CLS by data save mode values
Once you’ve improved CLS, set an alert to be the first to know if it starts worsening again.
Try it yourself
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