Does Heroku support Domain Masking?

Resolution

Domain masking is a technique that some DNS providers offer that hides the real address of the website being access. E.g., Using domain masking, when browsing to http://yourdomainname.com, the DNS provider creates a page that, using HTML Framesets, frames your application from http://yourapplication.herokuapp.com. So the user sees pages from your application, but by using the herokuapp.com domain to get these pages. Put simply, the real domain, yourapplication.herokuapp.com has been masked to make it look like http://yourdomainname.com.

This is an inherently insecure approach to DNS, and most modern browsers will refuse to show any framed pages from a different domain.

We don't recommend using domain masking for this reason. Instead, we recommend setting up your DNS to use a CNAME for your domain. You can read more about this here: Custom Domain Names for Apps