I love ssh apps! See also late.sh, and my own https://shellbox.dev
ssh applicant@register.public.outband.net
The web page https://www.public.outband.net hosted on the same box, if you can see it you have the needed ip6.
No users yet but feel free to try it out.
;; communications error to 2001:470:4b:27e:8::#53: timed out