EDIT: To check if user is ‘made-up’ or ‘real’, just send an email verification by calling FirebaseAuth. instance. currentUser. sendEmailVerification() and ask user to click the link sent in their email , if user is able to perform this action then email exists otherwise it’s ‘made-up’.
Read moreHow do you get a user email in Flutter Firebase?
Follow the steps to Firebase email and password authentication in the Flutter application.
Read moreHow do you get current logged in on Flutter?
In the following steps, you will be able to build app a get current user.
Read moreHow does authentication work in Flutter?
Upon completion of the sign-in transaction, the users authenticate with the authorization server and return to the application . Inside the AuthorizationTokenResponse result object, you receive three tokens: accessToken : an OAuth 2.0 artifact that allows the application to call secure APIs on behalf of the user.
Read moreHow do I use Firebase authentication?
Get Started with Firebase Authentication on Websites
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