At Trustpilot, we take page loading speed seriously. We optimize our TrustBoxes continuously because we want our customers to get the most out of our widgets without disrupting the performance of their websites.
How does a TrustBox affect the weight of a webpage?
The average webpage weighs around 2MB, while eCommerce sites weigh up to 5MB-7MB or more (from 2016). Add a TrustBox into the mix, and you should expect between 50 and 120 kilobytes of extra weight, depending on what kind of TrustBox it is and how much data it displays.
Now, these numbers are based on uncached requests. When loading the page a second time with browser caching, our requests account for about 1.5 kilobytes.
Not exactly a drop in the ocean, but the extra weight should not affect your website’s performance. In fact, this is standard for adding any element to a webpage.
The extra calls are minimal, and everything is loaded async, so it doesn't block any of the site elements.
Overall, the benefits of displaying reviews, your TrustScore, and star rating on your website are worth the added weight.
How does a TrustBox affect the PageSpeed of a webpage?
Your PageSpeed Insights score may drop 1 or 2 points, as should be expected when adding any additional element to a website.
Here’s an example of what a page with a TrustBox looks like compared to an empty page:
How does it look like in PageSpeed Insights?
The Trustpilot API calls (reviews, TrustScore, and star ratings) are cached for 30 minutes to ensure that content is up-to-date. This triggers the leverage browser caching rule because PageSpeed Insights detect that the resources are specified to be cached for only a short period.
Fetching these resources does not delay processing nor does it block the rendering of page content. Furthermore, you should expect an added weight of around 10 kB from these calls.
How does the loading time of TrustBoxes impact SEO?
Page speed is one of the many factors that can affect SEO. As long as the overall page load is not too slow, the TrustBox should not have any major negative impact on your SEO.
We recommend reading these threads on PageSpeed with feedback from Google employees:
“Yesterday, Gary Illyes from Google told a webmaster not to "worry about it too much," when it comes to page speed.” From: Google: Don't Worry Too Much About Page Speed
“I don't know how much of that [PageSpeed ranking factor] is still used at the moment. So we do say we have a small factor in there for pages that are really slow to load where we take that into account. But I don't know how much that's actually still a problem in ranking.” From: Is There Still A Google PageSpeed Ranking Factor?