I want to allow people to privately share data with each other using their contacts list to select people to share with. I’m planning on using Push Notifications to notify others that they have been shared with, but how can I handle those that do not have the app installed?
The cases are that I have their phone # and/or email. I can simply send them a message saying “X wants to share Y with you”, but how can I determine if I need to send a Push Notification or an email/text?
If you’re looking for API then you’re out of luck. You can always collect this personal data server-side with agreement of your users. There you can also manage groups and other community relations.