Can CDN be added for a site without it question

He all.
I have been wondering if it is possible to compare Imaginary a site with CDN, in fact it does not use it
as I can check now - with js and without js enabled

Is it possible to do so on WebPageTest?

Potentially though you’ll need to take care of configuring the CDN itself (without necessarily changing the site). Say for example, doesn’t use a CDN.

  • Pick a CDN provider and configure it to point to’s server as the source
  • Tell the CDN that you want to use for the domain name
  • Most CDN’s will give you a unique DNS name that you will need to CNAME to (like or something like that)
  • In WebPagetest you can use the SetDnsName to map to so it will test through the CDN without you having to change the site’s DNS or anything about the site

You do still have to do all of the legwork in setting up the CDN as if you were going to use it though.

Thank you for answer,

I really need your help - I have watched almost all of your Webinars . Did the best of your recommendations and get this

When I deffered the main JS I got worse Page speed index compare to almost the same version with Main js footer…

could you please give insight - why ?

The speed index is getting thrown off by that giant white popup and dimming of the main page. Your best view for debugging is the filmstrip like this:

It looks like the page basically all renders after the html and one css file have loaded (and it squeaks the image in there as well). The main pain point is the server time to generate the HTML which is ~750ms. A CDN will only help if your HTML itself is cacheable and you can cache it at the edge. Otherwise going out to a different domain for the CSS and image will actually make it slower.

The javascript isn’t coming into play in the initial render at all.

Oh, thanks, Patrick

1 - I will look deeper how I can speed up appearing of “Welcome message” pop with no content inside)
2 - I would try to Deffer inlined GA script - to start render as fast as possible - will help ?
3 - Will it help to add async tag for main js in order to get look ahead parser preload next assets

As for First byte - it is a Dev instance . It should be twice faster on Live instance


Could u give ideas why waterfall is so bad
I dont have like
6 connections
6 connections
6 connections,

1 con
2 con
3 con and so on