To configure kitty to use rifle:

Add the following to ~/.config/kitty/open-actions.conf :

protocol http, https
action launch --type background rifle -- ${URL}

This is for any http,https protocol. Ideally I would have no filtering but the manual says that at least one condition is required.

I needed the --type background to avoid creating a temporary kitty window. The -- ${URL} is to avoid issues with whitespaces or hyphens