Domain configuration for website with and without www

Question

I have a heroku app with the following settings:

Domain name: www.localhost.com
DNS Target: safe-springs-1527.herokuapp.com

The domain is on GoDaddy. The settings there are:

A (Host) 
0 Records (0 Selected)

AAAA (IPv6 Host) 
0 Records (0 Selected)

CName (Alias) 
Host Points To
email   email.secureserver.net
ftp safe-springs-1527.herokuapp.com
www safe-springs-1527.herokuapp.com

When I try to createa a CName record which will be with host "@" and to point to "safe-springs-1527.herokuapp.com" I get the error The specified record already exists. CNAME - @.

My website is accessible when I use www.localhost.com but not when I use localhost.com.

I also have in mind what is needed is an A record which points to an IP. Unfortunately heroku gives me a dynamic host which its IP changes.

I posted this issue on reddit and through the discussions I understood that what I am trying to do is not possible and the only solution would be to move to CloudFlare. I am not sure if I have to move my domain or app there but my concern is different. I just can't grasp that. I can't believe that all apps on heroku have this issue.

Is this the case or am I missing something (on heroku's or godaddy's end or...)?

Answer 1

I found this on Heroku and now my domain works fine without the www. I am not sure what it does.

In short:

Root domains must be added in addition to any subdomains. The process for adding root domains is the same in the Heroku CLI:
$ heroku domains:add example.com
Adding example.com to example... done
!    Configure your app's DNS provider to point to the DNS Target example.herokuapp.com
!    For help, see https://devcenter.heroku.com/articles/custom-domains

Answer 2

Use http://redirect.name/ and set the DNS records it specifies there to redirect your www domain to the naked domain, or vice-versa.

Apparently it is better for SEO to have one "canonical" domain, with or without www. The other should be a redirect.