You can load and play websites from arbitrary URLs using the HTML producer like this:
PLAY 1-10 [HTML] "https://www.indr.ch/"
Or, if you are restricted to CG commands (such as from a client software), and you are using at least server version 2.2.0 Beta 7 you can load any URL as a template via CG commands like this:
CG 1 ADD 0 "https://www.indr.ch/" 1
If you are still using an older server version, have a look at this short guide Loading and playing websites from arbitrary URLs with CasparCG that shows you how you can achieve the same result on any server version! Cheers!
Related: Play HTML from local directory