How this site performs

This page contains web performance stats for this website. It's taken from real user monitoring, which I've added using Boomerang.

Real user monitoring works by sending a beacon containing performance data for every visit to a page on the site. This makes it a good way to gain insights into the experience a website delivers.

Not every test reports on every metric – for example, some browsers don't support first contentful paint.

I've just picked out a few metrics to highlight on this page.

Response start

When the first byte of data is delivered to the browser.

First contentful paint

This aims to measure the point at which people can begin to consume content on the page.

DOMContentLoaded

The DOM and CSSOM are likely to be ready at this point. DOMContentLoaded can be important because some scripts will wait for this event before executing.

Onload

The time it takes for all the resources on the page to finish loading – although this excludes script-injected assets that are fetched only when the onload event has fired.

Response start

PageMedian (ms)
www.alexrp.co.uk/blog/speed-index-and-ux.html488
www.alexrp.co.uk/blog/preloading-fonts.html506
www.alexrp.co.uk/505
www.alexrp.co.uk/blog/resource-hints-prerender.html505
www.alexrp.co.uk/monitor.html501
www.alexrp.co.uk/blog/web-performance-special-cases.html488
www.alexrp.co.uk/blog/fast-single-page-apps.html479
www.alexrp.co.uk/blog/web-performance-black-friday.html488
www.alexrp.co.uk/blog/ab-testing-and-web-performance.html503
www.alexrp.co.uk/about-web-performance.html505
www.alexrp.co.uk/links.html501

First contentful paint

PageMedian (ms)
www.alexrp.co.uk/blog/speed-index-and-ux.html634
www.alexrp.co.uk/blog/preloading-fonts.html653
www.alexrp.co.uk/653
www.alexrp.co.uk/blog/resource-hints-prerender.html652
www.alexrp.co.uk/monitor.html643
www.alexrp.co.uk/blog/web-performance-special-cases.html634
www.alexrp.co.uk/blog/fast-single-page-apps.html627
www.alexrp.co.uk/blog/web-performance-black-friday.html634
www.alexrp.co.uk/blog/ab-testing-and-web-performance.html650
www.alexrp.co.uk/about-web-performance.html652
www.alexrp.co.uk/links.html644

DOMContentLoaded

PageMedian (ms)
www.alexrp.co.uk/blog/speed-index-and-ux.html783
www.alexrp.co.uk/blog/preloading-fonts.html811
www.alexrp.co.uk/810
www.alexrp.co.uk/blog/resource-hints-prerender.html810
www.alexrp.co.uk/monitor.html803
www.alexrp.co.uk/blog/web-performance-special-cases.html782
www.alexrp.co.uk/blog/fast-single-page-apps.html763
www.alexrp.co.uk/blog/web-performance-black-friday.html780
www.alexrp.co.uk/blog/ab-testing-and-web-performance.html808
www.alexrp.co.uk/about-web-performance.html810
www.alexrp.co.uk/links.html803

Onload

PageMedian (ms)
www.alexrp.co.uk/blog/speed-index-and-ux.html1129
www.alexrp.co.uk/blog/preloading-fonts.html1178
www.alexrp.co.uk/1178
www.alexrp.co.uk/blog/resource-hints-prerender.html1172
www.alexrp.co.uk/monitor.html1161
www.alexrp.co.uk/blog/web-performance-special-cases.html1129
www.alexrp.co.uk/blog/fast-single-page-apps.html1093
www.alexrp.co.uk/blog/web-performance-black-friday.html1128
www.alexrp.co.uk/blog/ab-testing-and-web-performance.html1171
www.alexrp.co.uk/about-web-performance.html1178
www.alexrp.co.uk/links.html1161

Resource timings for latest test

The following waterfall chart is taken from the most recent test (excluding tests of this page) and gives an indication of how long it took to load the resources on that page.

www.alexrp.co.uk/blog/preloading-fonts.html
www.alexrp.co.uk/css/common-v2.css
www.alexrp.co.uk/fonts/fontos.woff2
www.googletagmanager.com/gtag/js?id=UA-148024686-1
www.alexrp.co.uk/images/img-ahead-of-font.png
www.alexrp.co.uk/images/preload-930.png
www.alexrp.co.uk/images/font-film.png
www.alexrp.co.uk/images/devtools-no-preload-860.png
www.alexrp.co.uk/images/devtools-preload-860.png
platform.twitter.com/widgets.js
www.alexrp.co.uk/images/feed-icon-28x28.png
www.google-analytics.com/analytics.js
www.alexrp.co.uk/images/banner-2560.jpg
www.google-analytics.com/r/collect?v=1&_v=j83&a=588521087&t=pageview&_s=1&dl=htt...
platform.twitter.com/widgets/widget_iframe.1b3bc218a38dc1163b7a53028a57ef50.html...
platform.twitter.com/js/button.660a9fead67f97981c42cfef39d63eda.js Short bars indicate retrieved from cache
platform.twitter.com/widgets/tweet_button.1b3bc218a38dc1163b7a53028a57ef50.en.ht...
Time:1s2s3s4s5s...