OAuth2 Redirect URLs

I’m writing a Service Manager for a cloud device, with OAuth2. In the documentation, it defines OAuth2 redirect urls as:

redirect_uri: “https://graph.api.smartthings.com/api/token/${state.accessToken}/smartapps/installations/${app.id}/receiveToken

whose value depends on the run time. But in my backend, when I register the SmartThings application on my OAuth2 provider, I need to put in a fixed redirect_url. Maybe I’m misunderstanding something here? Any help would be greatly appreciated. Thanks a lot.

It is fixed… For the user

So why in the documentation it is made up of several fields that can only be evaluated in run-time? Do you know how to deal with this issue? Thanks.