Audit Third-Party Script Impact

Third-party scripts are one of the most common causes of poor web performance. Analytics trackers, chat widgets, A/B testing tools, ad networks, social media embeds, and marketing tags all compete for bandwidth and main-thread execution time. On many sites, third-party scripts account for more than half of total page weight and JavaScript execution time.

Lighthouse identifies third-party resources and measures their impact on loading performance, main-thread blocking, and network utilization. This data helps you make informed decisions about which scripts provide enough value to justify their performance cost, and which should be deferred, loaded conditionally, or removed entirely.

This audit is particularly important for marketing-heavy sites where tag managers have accumulated dozens of scripts over time. Often, nobody is tracking the cumulative performance cost, and removing a few unused scripts can dramatically improve page speed.