Shiny apps are a great way to share information and empower your users. Sometimes you want to make sure that only authenticated and authorized users will be able to view your shiny apps.
There are a number of ways to make sure only certain users have access to your apps. For example, you can subscribe to the professional plan in shinyapps.io which has this option built-in. You can program the authentication flow internally by yourself, or you just use a 3rd party service such as google firebase, AWS Cognito, Auth0, or others).