Currently, in order to run an app via the API, you have to have uploaded the app to your private studio. Frankly, I don't find this function useful because you have to download then re-upload an app in order to gain access to the API. The API would be more useful if when an app is shared with you (or a collection is shared with you), then it would also allow for that app to be run via API by the user it was shared with. Right now, the only person who can run the app via API is the user who originally uploaded said app.