Is there a way to use the PDF Embed API with an IP address or internal domain?

I’d like to use the PDF Embed API. I was able to register the localhost domain and confirmed that it works correctly.
However, after hosting it on a server for testing, I need to access it via a private network using either an IP address or an internal domain (which doesn't have a public URL).
It seems that IP addresses cannot be added to the list of allowed domains, so in this case, is there any way to use the PDF Embed API?