When using routes like from "nike.domain.com" to "/client/nike", Bubble will only work with a client route (iframe) handler. If you don't want to load a page using a client route handler you have to use the custom domain name to load the correct data. That's because Bubble slugs (in this example nike is the slug) and parameters (like ?client=nike) only work with client-side routes.
In this tutorial, we will have a page called client. This page loads data from a database thing called landingpage.
1. First we add a new field on the landingpage thing called domain. That field has a value like "nike.domain.com".
2. We add the element Multi Domains (from the bubble plugin) to the page client
3. We create a group on the page called "get my landingpage" and we set type of content to landingpage and set the datasource to search for landingpage with constraint domain = multi domains a's hostname
4. Now we can use refer to the group "get my landingpage's Landingpage" to build the entire page and get all the data
This way you can load the correct data for the page using the custom domain and without using the slug.