Hi there,
Each custom domain requires its own separate Webflow site with an active Site plan. While you can create unlimited sites with a Starter Site plan (free), publishing to a custom domain requires upgrading to a paid Site plan for each individual site. This means if you want to publish to three different custom domains, you’ll need three separate sites, each with its own paid Site plan.
The Starter Site plan allows you to design and develop your site, but publishing capabilities are limited to Webflow subdomain (yoursite.webflow.io). For custom domain publishing, you can choose from Basic, CMS, Business, or Enterprise Site plans based on your specific needs.
Hopefully this helps! If you still need assistance, please reply here so somebody from the community can help.