Does PSI uses client IP to access the requested URL?

Question

Does PSI uses client IP to access the requested URL or it uses any internal network IP address?

We would like to allow only PSI to access our website.

Answer 1

PageSpeed Insights does not publish a fixed set of IP addresses (see here for previous discussion on this).

I would advise running Lighthouse Separately (via CI or via DevTools) which will get you the same lab-based analysis. Though be aware it can have different settings.

For the field analysis shown at the top, your site needs to be public anyway.