Any way to force HTTPS using external IP on snap RC?

By default RC uses HTTP is there any options somewhere I can change this to HTTPS?
Caddy requires to use DNS record to enable https but I want to use IP. I dont need valid SSL cert just need to be able to access RC using HTTPS because some API’s we are testing that require to have https. With Apache or Nginx I can just edit the conf file not sure if there is any option for this when RC is installed using snap.