Hotjar: impact on page speed
Category: Session recording and heatmaps
Hotjar records sessions and builds heatmaps by observing changes to the page while the visitor interacts with it. That observation runs on the main thread for as long as recording is active.
On 3.0 % of the 5509 homepages measured, Hotjar is among the five heaviest third parties. Where it is, it takes a median of 77 ms of main-thread time; on the heaviest quarter of those sites it takes 102 ms or more.
3.0 %
of homepages: among the five heaviest third parties
77 ms
median main-thread time
102 ms
main-thread time on the heaviest quarter (p75)
64 KB
median transfer size
Distribution across homepages
Percentiles across 165 homepages with Hotjar.
| Percentile | Main-thread time | Transfer size |
|---|---|---|
| p25 |
60 ms
|
64 KB |
| Median |
77 ms
|
64 KB |
| p75 |
102 ms
|
66 KB |
| p90 |
220 ms
|
69 KB |
In context
By median main-thread time, Hotjar ranks 45th of 72 third parties in the benchmark, lighter than Cookiebot and heavier than mPulse.
On 7.3 % of the homepages where it appears, Hotjar alone uses 250 milliseconds of main-thread time or more, the mark from which Lighthouse flags third-party code.
Homepages with Hotjar weigh 4.8 MB at the median (JavaScript: 1.9 MB), homepages without it 4.2 MB (JavaScript: 1.5 MB).
Often loaded together with
Share of homepages with Hotjar where the other tool is also among the five heaviest third parties.
- Google Tag Manager 87 %
- Facebook 55 %
- TikTok 23 %
How to spot Hotjar on your page
The loader comes from static.hotjar.com and pulls its recording modules from script.hotjar.com; settings and content are fetched from content.hotjar.io. Unlike a pixel that fires once, a recorder keeps working during scrolling and typing, which is why it shows up in Interaction to Next Paint rather than only in load time. Teams that review recordings once a quarter rarely need the script running the rest of the year.
How to reduce the impact of Hotjar
- Run recordings for a defined analysis period instead of permanently.
- Limit recording to the pages you are actually analysing and sample a share of sessions.
- Load the script only after consent.
Frequently asked questions
How can I load Hotjar with less impact?
Run recordings for a defined analysis period instead of permanently. Limit recording to the pages you are actually analysing and sample a share of sessions.
Does Hotjar affect Core Web Vitals?
Hotjar records sessions by observing every change to the page and every click, scroll and input. That observation runs on the main thread for the whole visit, so INP is the metric it affects most. Survey and feedback widgets add visible elements that can shift the layout if they appear in the page flow instead of as an overlay.
Method and sample: Third-Party Benchmark.