I am trying to understand whether the ArcGIS Online licensing allows me to create a proxy to attach credentials to requests to a private hosted feature service.
An example use-case would be an application where we have implemented our own authentication and then want to supply secure data from our organisation to the user in the application.
I can see that there is somewhat a mechanism to do this using the Esri Developer API keys, but the terms of use indicate that this cannot yet be used commercially:

I would appreciate any insights or recommendations on the matter. For example what would the recommended mechanism be to achieve the above workflow? Thank you!