I've the following problem with an app I'm developing who is going to be offered worldwide in Google Play.

The app asks for very very personal data, so I think that in order to decrease user's suspicion it's better to use an email instead of a phone number as a way of recognizing the user, indeed in configuration process I even tell the user that he can use the app through a proxy with Tor or similar to feel more secure.

Problem comes that I'd like the user not to do some operations in the app if he has done beforehand some of them, even if he uninstalls app.

But with email identification, if the user is slightly clever he's going to realize that all he needs to bypass the protection is using another email account and I've no way to know it's the same user, (this could also happen with the phone number, although to a very lesser degree).

So it looks like I have to choose into allowing the operations I'd like to avoid or having user distrust, it looks like I'll have to choose the first thing.

Anyway maybe there's something I could do so users get to trust the app more. Do you have any idea of what could I say?

  • 1
    Well, what exactly does you app do? And what "very personal" information does it collect? It's impossible to give you suggestions unless we know the exact scenario.
    – musefan
    May 14, 2021 at 11:35
  • Opinions in things like politics, controversial themes and so on, I don't think it's neccesary to say which one exactly, but the one you are not likely to go airing in a public way as it's likely to cause you problems. May 14, 2021 at 12:12
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    In that case, sounds like you might struggle to even get a proper email address from the users. I would suggest giving up on the phone number approach, I think you are right that people won't be happy to do that and also be honest with their opinions. Just my thoughts though.
    – musefan
    May 14, 2021 at 12:14
  • Why would users provide this data: what is in it for them ?
    – PhillipW
    May 17, 2021 at 11:44
  • @PhilipW, that data absolutely needed for the app's purpose, I can not tell what's exactly for as I could have the idea stolen, anyway when I release it I could show to you, anyway people usually tell their views on politics and controversial issues via chatting app like Whatsapp, although it's not directly requested. May 17, 2021 at 13:30

1 Answer 1


You can ask for email in the onboarding and then ask user to update the profile like with some additional fields including the phone number to use the rest of the functionalities in the app

this way you have a chance to win user in the onboarding/first use of the app

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