alexpoof

For my domain (https://www.poof.io), it's www.

If you just use something like https://poof.io, then it would be @. Depends on your site.

There should be a few historical IP addresses, but you would create an A record for each of them.

Used this site https://www.whatsmydns.net, and it worked.

Unfortunately the Heroku issue lost us a few thousand $ alongside a few customers.