Can I serve my Web Client Hosting app from the root of my domain, without /app/ in the URL?

Not directly: Catalyst CloudScale Web Client Hosting serves your web client under the /app/ path, also on a mapped custom domain. To serve it from the root, including files such as robots.txt or a sitemap, route requests through Catalyst CloudScale API Gateway:

1. Plan first: when you enable API Gateway, Security Rules are disabled and all your function and web client URLs are inaccessible until you create APIs for them. API Gateway is a paid component.
2. Open CloudScale → API Gateway (under Security & Identity), click Enable Now, then Proceed.
3. Create APIs for all your functions. Auto-create is available only until you create your first API.
4. Click Create API, select GET, enter the request URL /{path:(.*)}, select the web client as the target, append {path} to its target URL /app/, and click Create.
5. Test the default application URL and your custom domain.

Alternatively, host the site on Catalyst Slate, Catalyst’s frontend hosting service.

Refer to the API Gateway Key Concepts help page and the Web Client Hosting Introduction help page for details.