Current state
Custom domain provisioning is not yet available in the dashboard. The domain settings UI is a placeholder while the DNS verification pipeline is being finalized.
Your store is currently accessible at justmy.site/store/your-slug.
Custom domain support is on the near-term roadmap.
How to prepare
Choose the subdomain you want to use, such as store.yourdomain.com.
Keep access to your DNS provider so you can add a CNAME record when the feature launches.
You will need to point the CNAME to a platform-provided target when prompted.
What happens when it launches
You will enter your domain in Settings then Domain.
The platform will provide a CNAME value to add to your DNS.
After DNS propagation, the platform will verify the record and activate your custom domain.
Your store will be accessible at both the custom domain and the original slug URL during the transition.