How to check your website’s performance?

Just recently, a friend of mine asked me about “website analysis tool”. I got interested and immediately started asking questions. What would you like to analyze? Performance? SEO? Accessibility? “We would like to check our website for performance.”, he says. Luckily, a couple well established tools exists that are designed to do just that. I this post I will list both and provide a general overview for each.

WebPageTest

Url: https://www.webpagetest.org . In my opinion this is the best freely available tool for measuring website performance. Just provide your website url and the service will perform detailed load analysis of each request that originated on your website and much more.

Their testing uses emulated devices with emulated internet speeds. Please note that although your internet speed may be quick, fast average internet speeds are not guaranteed in other places in the world. Here is an example of the report:

Performance Summary Report from WebPageSpeed

From the screenshot above look for number that are red colored (obviously). In this case “Total Blocking Time” could be improved by changing into asynchronous load for the offending requests. Which request you may ask? Scroll down the report to see more details. In my case I see this:

WebPageSpped Report Detail View
Real life WepPageTest report from my page.

Aha, request #3 needs to loaded asynchronously.

This report also supply us with time to first byte (TTFB). This is the time when browser gets first byte of first response. Anything below 800ms is great, anything between that and 1800ms needs improvement but anything above 1800ms is a problem that needs to addressed as soon as possible. Problem with TTFB could be caused by server misconfiguration or inadequate server specs. This could also be caused by heavy dynamic content which needs to be retrieved from databases or other systems without appropriate caching system.

But, event the fastest TTFB won’t help when contents of your webpage are just heavy stuff. For example, videos. Videos could could easily take over 10MB is bandwidth and serving them for all users should be meticulously considered.

PageSpeed Insights

Url: https://pagespeed.web.dev . This is Google online tool that measures website performance, accessibility, SEO and good practices on both mobile and desktop versions of your website. Along with overall score the tool provides detailed measurements and practical remedies for website under the test. Here is an example of this preview:

PageSpeed Insights Report Example
Real score from PageSpeed tool.