SiteSpeed

Introduction

Fanplayr SiteSpeed captures realtime performance metrics for pages and resources loaded on your website. Instead of relying on website crawlers to sample and approximate the performance of your site, SiteSpeed captures metrics directly from the unique perspective of each visitor to paint an accurate picture of performance for every page from all devices and locations.

Measuring performance

DOM Interactive time

The primary metric used to measure the performance of each page visited is called the DOM Interactive time. This event is emitted by the browser when it has finished loading and parsing the initial HTML document and all initial render blocking resources such as scripts and stylesheets. Fast DOM Interactive times are critical for delivering satisfying experiences for your users.

Apdex rating

Fanplayr calculates Apdex ratings to provide you with a single metric that can help measure user experience. This is a standardised way of measuring any user experience metric and SiteSpeed uses this the DOM Interactive time for this algorithm.

Fanplayr analyses all of your page views to calculate a baseline of what a typical "fast" page time is for your site. This is what is referred to as the Satisfactory time, and any page view with a DOM Interactive time below this value adds to your overall user experience. Page views up to 3 times as slow as the satisfactory time are considered to be Tolerated views, while anything slower than that can lead to a Frustrated user experience. The distribution of page views that fall within these three categories are combined to product an Apdex rating between 0 and 1 to provide an indication of overall user experience.

• An Apdex measurement rating between 0.94 to 1.0 equates to Excellent performance.

• An Apdex rating above 0.85 equates to Good performance.

• An Apdex rating between 0.7 and 0.85 equates to Fair performance.

• An Apdex rating below 0.7 equates to Poor performance.

• An Apdex rating below 0.5 is considered Unacceptable.

An example of overall Apdex Performance rating and distribution.

Ecommerce KPIs

DOM Interactive times are plotted against key ecommerce metrics to help illustrate how page load performance can affect your conversion rates, AOV and bounce rates.

Geographic measurements

SiteSpeed also visualises DOM Interactive times from every corner of the globe. The colour scale represents the faster regions as blue while slower regions are red. Clicking a country allows you to drill down into its states or provinces to see performance timings from smaller regions. In this zoomed in mode, the size of the markers also represent the number of page views from that location. You can hover over markers which are tightly grouped together to show a magnifying glass of that area which allows you to pinpoint individual regions. (Click the video below to see it in action!)

Performance by page and resource URLs

Various tables break down performance by page, device and even on the individual resources level. The resource tables show the Duration metric which is the total time taken for the browser to download the resource.

Limitations

Number of resources captured

Modern web browsers capture performance metrics for the first 150 resources loaded on a page by default. This means that Fanplayr's resource measurements may not represent all requests made for pages that rely on large numbers of assets.

This default limit can be increased easily by adding a small amount of JavaScript early on in the document to increase the performance entry buffer size with a new maximum limit:

<script>
if (window.performance) {
  performance.setResourceTimingBufferSize(/* NEW LIMIT */);
}
</script>

It is worth noting that increasing this limit will raise the amount of memory used by the browser and increase the amount of bandwidth used by your visitors when transmitting the metric information to Fanplayr. You should consider the impact increasing this default limit may have on your users before making any changes. For example, mobile visitors tend to have more memory and bandwidth constraints, particularly when they are browsing over cellular internet connections.