To point your apex/root/naked domain at a Heroku-hosted application, you'll need to use a DNS provider who supports CNAME-like records (often referred to as ALIAS or ANAME records). Currently Heroku recommends:
Whichever of those you choose, your record will look like the following:
Record: ALIAS
or ANAME
Name: empty or @
Target: example.com.herokudns.com.
That's all you need.
However, it's not good for SEO to have both the www version and non-www version resolve. One should point to the other as the canonical URL. How you decide to do that depends on if you're using HTTPS or not. And if you're not, you probably should be as Heroku now handles SSL certificates for you automatically and for free for all applications running on paid dynos.
If you're not using HTTPS, you can just set up a 301 Redirect record with most DNS providers pointing name www
to http://example.com
.
If you are using HTTPS, you'll most likely need to handle the redirection at the application level. If you want to know why, check out these short and long explanations but basically since your DNS provider or other URL forwarding service doesn't have, and shouldn't have, your SSL certificate and private key, they can't respond to HTTPS requests for your domain.
To handle the redirects at the application level, you'll need to:
heroku domains:add example.com
and heroku domains:add www.example.com
)www
pointing to www.example.com.herokudns.com.
SECURE_SSL_REDIRECT
to True
)Check out this post from DNSimple for more.