What is PLS by third-party script
PLS by third-party script reveals how Perceived Load Speed (PLS) is impacted by the presence of third-party scripts — such as analytics, ads, chat widgets, social media embeds, or personalization platforms.
Since third-party scripts often load independently from your core site assets, they can delay the visual completeness of the page and negatively affect how fast it feels to your users.
Healthy PLS by third-party script sample
Should you worry
A healthy state occurs when third-party scripts are present, but the perceived load speed remains fast. This often means scripts are well-optimized, deferred correctly, or loaded after critical visual elements have appeared.
Well-performing sites find ways to keep essential content visually complete while deferring or controlling third-party execution.
If certain third-party scripts consistently lead to higher PLS (slower perceived load), they may be harming user experience without providing enough value in return. This can happen even if those scripts don’t impact LCP or technical load metrics, because users perceive the page as unfinished while those scripts load in the background.
This is especially critical for first impressions — like landing pages or key conversion paths — where slow visual completeness causes hesitation or early exits.
Unhealthy PLS by third-party script sample
An unhealthy lens shows that pages using specific third-party scripts consistently have slower perceived load speeds. This pattern usually stems from blocking scripts, heavy third-party assets, or delayed layout completion caused by async dependencies.
These scripts may delay when key elements appear, shift layout unpredictably, or block interactions — leading to reduced engagement and higher bounce rates.
Resolving unhealthy PLS by third-party script
Go-to action plan to resolve an unhealthy PLS by third-party script:
Ask Uxi to analyze your PLS by third-party script and suggest improvements.
Use Filters to compare the same page with and without certain scripts to measure their impact on visual load time.
Simulate LCP of the suspected lens to see if fixing it will resolve the PLS by third-party script. If yes, this is where the resolution focus should be.
Use an automated optimization tool like Navigation AI to improve your PLS by third-party script.
Once you’ve improved PLS, set an alert to be the first to know if it starts worsening again.
Try it yourself
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