Hey @yw662, the wildcard subdomains, which would use a wildcard CNAME, is a feature we can enable for Pro or higher accounts 
@mak here’s a bit more info for you on the feature, please feel free to follow up if there are more questions:
The wildcard subdomains feature is one we can enable on a Pro account or higher. This means you could have a custom subdomain for each of your customers, i.e. customer1.yourstore.com, customer2.yourstore.com, etc. all pointing to the same underlying site. If you’re using Netlify DNS to host your DNS, we can take care of the SSL certificate for this configuration. Otherwise, you’ll need to bring your own wildcard SSL certificate.
A few caveats about this feature:
- You can’t use domain aliases on a site with wildcard subdomains enabled, just the bare domain and subdomains under your primary domain. If you try to add a domain alias then it won’t work.
- The primary custom domain for the site, if it is a “site.com+www.site.com ” setting in our UI, must be www.site.com and NOT site.com!
Let us know if this helps or if we can answer any other questions!