App with no login and saving info against IMEI

Question

I don't have any login for my app.

I want to use a unique identifier to store user details. I cannot use FCM ID or unique Identifier/GUID bcs once user will clear the cache or reinstall the app I will get a different FCM ID or unique Identifier/GUID.Now to the extend I know I've only option left that is to use IMEI as a unique identifier and save the app data against IMEI in DB, but I came across some posts saying rooted devices always have 000000.. IMEI.

Kindly suggest should I use IMEI or not. If yes then what I should do for rooted devices?

Answer 1

Take a look at this thread and see if this can help you: Is there a unique Android device ID?

It shows you how to get a unique Android ID.

Answer 2

No, IMEI shoudn't be used in this case, same for any other hardware related stuff. Just add login/register functionality to your app, it will be the best option for everyone. Also take a look here: https://developer.android.com/training/articles/user-data-ids.html