I've been building a web app which will be served to users via a native webview. I have been using This monitoring Tool to monitor visits and page views but it really does not provide the stats that I need, which is the real number of people actually using my app.

I think, If I could create a js code and serve it withing the index page of the app, so this js code can collect some unique device "something" and create a database with that info, so, everytime a user uses the app this same js code, or something else, could recieve that unique device "somethig" and compare it to the database, if it already exists is not counted as a new user as it has been counted before. But if it does not exist then it would be a new user.

I must state that the app would be hosted on a shared hosting and the webiew app will not be at Google Play but delivered to users in different ways. So, what I really need to know is:

1- Is it the logic I am using correct? Can it be done?

2- Which could be that unique device "something" other than IMEI, phone number or unique device ID?

I know it's not the usually accepted kind of question used to post here but I do not want to dive into some coding without beeing sure it will be usefull. So, depending on the answers I would try it out in practice and reshape this question to fit the Site's guidelines.

Thank you all in advance.