Michael Gearon

WebPageTest Obscure Features for Performance Testing

Michael Gearon

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WebPageTest for those who haven’t used it can allow anyone, for free, to test their website performance by entering an URL and then viewing the results. The results are shown in a nice clear format with high level figures as well as more in detail figures. What this post will be about is the features that you may have not seen before which can be very useful.

Advanced Area

Before even starting the test there is the advanced area hidden as a dropdown link. This area allows you to setup your perfect test:

This area has a tonne of useful features such as:

  • Change the connection type is useful if you know your audience uses slower connection speeds this option can reflect the typical connection your users use.
  • If you click across to the Chrome tab you can also generate a Google Lighthouse report seeing your SEO, accessibility, performance, progressive web app and best practice score
  • If you click across to block in this text area you can block assets, so you could block third-party scripts to measure parts of the website you can control

Request Mapping

Once your website performance test is complete you can then generate a request map to identify what third party scripts are on your website, and where transmitted bytes are coming from as well as the size of your domain and how slow it is. Especially in a post GDPR world this can also be a great way to what are third-party scripts are also additionally requesting in the background.

Visual Comparison Tool

The visual comparison tool is useful for presentations as you can enter your website URL against your competitors and then see how long it takes for your website to load against your competitors.

You don’t have much control over where the test is run and all of the other more advanced features but because all of the URL’s are tested from the same location then it’s a fair performance test.

If you scroll down past the filmstrips you can then compare how your request load in against your competitors using opacity sliders, export the filmstrips, create videos and change the formatting of the filmstrips.

Setting up your own performance dashboard

WebPageTest has a good amount of documentation on it’s RESTful APIs so you can setup automated website performance testing. This could be useful as a way to monitor ongoing website performance and be part of a wider performance dashboard for people to view.


These are just some of the obscure features of WebPageTest. If you know any other useful features that you use on a day-to-day basis let me know. What you will find with WebPageTest is that it can very simple in that you can drop in a URL and quickly see the website performance or you can get a more in-depth really world experience where you can compare yourself to your competitors or see more details through the LightHouse reporting option.

Michael Gearon

Written by

Michael Gearon

Senior Interaction Designer and Co-Author to Tiny CSS Projects