In the following steps replace:
subdomainwith your desired subdomain.domain.comwith your domain.random.herokudns.comwith your Heroku DNS target (see step 1).
- In the Heroku deployment settings, under domains, click “Add domain”. Enter
subdomain.domain.comto receive therandom.herokudns.comHeroku DNS target. - In the Heroku deployment settings, under SSL certificates, ensure a certificate is automatically managed. If you don’t do this, attempting to visit
https://subdomain.domain.comin a browser will fail with an SSL error.