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

The knowledge could save precious milliseconds or even seconds of page loading time on your website – so let’s dive in.

The article was updated with the latest data on the 5th of September 2023. Up-to-date numbers are available at all times on the Third Party Web website.

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. But first, let’s look at how the top 10 advertising scripts perform.

Performance of the top 10 advertising scripts (sorted by popularity)

  • Google/Doubleclick Ads – 2027ms average execution time
  • Pubmatic – 533ms
  • Rubicon Project – 166ms
  • Criteo – 244ms
  • BlueKai – 118ms
  • Tynt – 99ms
  • Amazon Ads – 138ms
  • Klaviyo – 586ms
  • Media.net – 544ms
  • Crowd Control – 259ms

The results are certainly food for thought for marketers. Google Ads is the undisputed favourite due to its ease of use and scale, but perhaps the performance tradeoff could make other channels more appealing?

Coincidentally, six of the most popular scripts also make up the top six of the fastest advertising scripts. These are, in order of performance:

  • Tynt – 99ms
  • BlueKai – 118ms
  • Amazon Ads – 138ms
  • Rubicon Project – 166ms
  • Criteo – 244ms
  • Crowd Control – 259ms

Analytics scripts

The impact of analytic applications will vary depending on what’s being tracked. 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.

  • Google Analytics – 113ms
  • Hotjar – 437ms
  • Optimizely – 745ms
  • Nielsen NetRatings SiteCensus – 513ms
  • Lucky Orange – 1009ms
  • Histats – 1873ms

Social features

It’s hard to come by a website without social media features these days. Businesses want to promote their channels, often including extensive feeds on their websites. But this comes at a price. What is it exactly?

Pinterest adds a negligible 103ms to your load times. It’s also good to see that a social media “aggregator”, ShareThis, comes in at a respectable 315ms. On the flipside, those using Tumblr can see spikes of up to 2.4s.

Performance of social media scripts

  • Pinterest – 103ms
  • Facebook – 255ms
  • TikTok – 308ms
  • ShareThis – 315ms
  • AddThis – 973ms
  • Tumblr – 2418ms
  • Twitter – 343ms

Performance of marketing scripts

Most of the marketing solutions are well-optimised and have a similar average impact. HubSpot and Mailchimp seem to be slightly ahead of the mainstream pack. Surprisingly, big names like Sumo and Drift perform well below expectations.

  • MailChimp – 324ms
  • HubSpot – 397ms
  • Sumo – 1251ms
  • BigCommerce – 1808ms
  • Drift – 3348ms

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.

The fastest live chat scripts

We’ve seen a rapid decline in live chat performance since the start of the Third Party Web project, and here are the numbers:

  • Intercom – 672ms
  • Smartsupp – 729ms
  • LiveChat – 786ms
  • Tawk.to – 864ms
  • Jivochat – 986ms
  • ZenDesk – 1165ms

Cookie consent providers

Complying with cookie laws and GDPR is a tough task. Add to it the potential impact of third-party scripts and you’re staring down the barrel of another disadvantage for your company. Those that don’t bother with obtaining content get a performance advantage over you.

The Third Party Web report only notes the two following providers of consent:

  • Optanon – 301ms
  • Quantcast Choice – 433ms

The results are quite respectable, although our preference is still a bespoke solution based on Tag Manager. Google’s solution executes in 197ms on average.

Learn more about cookie compliance in the UK

How do pages with too many scripts affect website performance?

The disappointing answer is that it depends. But as a quick summary, shorter script execution times are almost universally better. This is because contrary to first-party assets, third-party scripts can be controlled to a lesser extent. Your developers won’t be able to influence some of their aspects and the performance will rely on factors that are mostly out of your control. There are ways to ensure that these scripts are not blocking the loading of critical assets of your page, but they will still affect the overall performance.

Why you need to measure the impact of third-party scripts: pros and cons

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.

It’s also important to note that the benchmark isn’t an apples-to-apples comparison with your website. While the values won’t be wildly inaccurate, you may see better (or worse!) performance on your site.

However, with page speed being one of the Google ranking factors, it’s worth being familiar with the impact of third-party services. Some scripts perform worse by an order of magnitude when compared to other solutions. When that happens, going for the slower script might be a costly mistake.

But on the other hand, third-party scripts often offer a wide range of features which would be otherwise very costly to implement for you. On top of that, many professionals are trained to use solutions based on website scripts. You don’t even have to look far to find the likes of Google Analytics and HubSpot. The latter can be a functional CRM without using scripts on your site, but at the same time, it would be wasted potential.

To find the updated values, visit the Third Party Web.

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Originally published Mar 14, 2019 6:36:20 AM, updated May 8 2024.

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