Improving the performance of a website can be hard. Using solid performance analysis tools is a must.

In order to run performance analysis using WebPageTest on a website that is protected by Cloudflare Access, you need to tell WebPageTest to authenticate.

First, manually access the website by entering your email and then the confirmation code. The next request sets a cookie with the key CF_Authorization.

That cookie can be set as header when running the performance test. Under Script you are able to define the steps that are taken by WebPageTest during the performance test.

setCookie https://%HOST% CF_Authorization=<value>
navigate %URL%