Trial & Error

The Impact of Scripts on Website Performance

Discover the third-party scripts that could be slowing down your website. Thanks to an open-source "Third Party Web" project by Patrick Hulce, a former Google Employee, we know how different scripts affect performance. The report covers popular services in a number of categories, from social features, through ads and analytics, all the way to marketing solutions.

Third-party scripts are responsible for most of the modern web usage. The “Third Party Web” report analyses over a million websites. Patrick Hulce‘s open-source project provides valuable insight into the impact of scripts on website performance.

The report was created with developers in mind. However, we have found the knowledge is valuable to website owners. Here’s our selection of script categories for you to consider when choosing third-party applications for your business site.

The article was updated with data from 15th May 2020.

Advertising services

Some of the third-party advertising services can single-handedly account for over half a second of your loading time. Recently, we’ve seen lots and lots of incredibly fast advertising scripts emerge. The majority of the top 20 loads in under 100ms, while previously we’ve seen entries from services that took twice as much time to fully load.

As of 15th May 2020.

One thing to keep in mind here is the role of these scripts. They are parts of advertising networks and the functionality might vary. Some might serve ads while other will serve and measure traffic at the same time.

Analytics scripts

The impact of analytic applications will vary depending on what’s being tracked. At the same time, the functionality of these services varies and in some cases, it’s not an “apples to apples” comparison.

Regardless, the list below contains some of the best and fastest analytics scripts out there. The speed won’t be the major factor here, as you want to focus on the best tool to gather and analyse your data. With that in mind, it’s good to see that most of the “big players” are among the fastest website analytics scripts.

As of 15th May 2020.

Social features

As of 15th May 2020.

It’s hard to come by a website without social media features these days. We are positively surprised by the performance of social integration services. Their scripts are faster than the sum of the individual social media features, especially with how disappointing Tumblr performs.

A popular comments section service, Disqus, will add almost a second to your load times, while Facebook doubles or nearly doubles the performance of the competitors, lagging behind their own Instagram.

Marketing solutions

Most of the marketing solutions are well-optimised and have a similar average impact. Our favourite, HubSpot, seems to be slightly ahead of the mainstream pack. Surprisingly, big names like Sumo and Drift have placed near the bottom.

As of 15th May 2020.

Customer service applications

79% of customers say live chat is their preferred communication channel but only 9% of companies use it. If you’re planning to integrate a live chat service with your website, this list can help you narrow down the choices to providers of the best performing scripts.

Most of the popular choices perform poorly, with ZenDesk reaching whopping 756ms and the most popular services ranking outside of the top 10.

As of 15th May 2020.

The key takeaways

As mentioned on a couple of occasions, these numbers need to be taken with a grain of salt. The best-performing marketing service might not be worth the gain if it doesn’t offer the features you need.

However, with page speed being one of the Google ranking factors, it’s worth to be familiar with the impact of third-party services.

To find the updated values, visit the GitHub page of “Third Party Web”.

Is your website slowing down?

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Originally published Mar 14, 2019 6:36:20 AM, updated October 22 2020.

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