LoadingSimple mode
External Scripts
Lists JavaScript loaded from third parties such as analytics, chat widgets, tags, or ad platforms, and highlights their weight and blocking behavior.
Why it matters
Third-party scripts are code you do not control, but they still compete for bandwidth, execution time, and CPU. A single badly loaded script can delay rendering or interaction for the entire page.
Where to run it
Available automatically in Simple mode.
Can also be explored in more depth from the underlying WebPerf Snippets reference.
Open analyzerWhat you learn from this test
Which external vendors are adding the most script weight
Whether any third-party scripts are render-blocking
Whether business tooling is imposing a visible performance cost
Common fixes
Remove low-value or duplicate tags
Load third-party scripts with async or defer where possible
Delay non-critical vendors until after the main content is visible
Audit tag manager sprawl and marketing pixels regularly