Even though I've added apps from gallery to Azure AD, I cannot see when I try to pull the data. But I can see the custom apps added. Like if I've added 7 apps; 2 from gallery(Google Docs, One drive) & 5 custom(native/web apps); I am able to see only 5 apps! Am I going wrong any where? The Graph API that am using is:
https://graph.windows.net/mycustomad.onmicrosoft.com/applications?api-version=beta
I tried with different api versions but no luck. Can someone suggest me on this?
In graph API, "applications" represent application configuration that developers register in their tenant. Gallery apps are no different (and happen to be registered in a special tenant). When you acquire an application (like a gallery app, or consent to a custom application someone else has developed), an application instance gets created in your tenant so that we can attach policy and permissions to it. This application instance is called a "service principal".
You can query for this using: https://graph.windows.net/mycustomad.onmicrosoft.com/servicePrincipals?api-version=1.5
This will return ALL acquired apps, and some default Microsoft apps.
Hope this explains why your query of the application entity shows only the custom apps you've registered in your tenant.
Hope this helps