title: How to implement Firebase phone authentication with Ionic 4?
body: <p>Is it possible to use phone authentication with Firebase and Ionic 4 in mobile apps? </p>
  
  <p>I have seen some old tutorials implementing phone authorization with Ionic 3, but these seem to be outdated. </p>
  
  <p>The firebaseui-web project does not support phone authentication for <a href="https://github.com/firebase/FirebaseUI-Web#cordova-setup" rel="nofollow noreferrer">cordova apps</a>, but I am unsure if that implies that Firebase phone authentication is impossible with ionic apps.</p>
  
  <p>If you cannot use Firebase's phone authentication with Ionic 4, is there an alternative phone authentication service that does work with Ionic 4?</p>