This is a demonstration of some features provided by the Firebase Plugins for Construct 3. Get the Plugins:
Firebase Auth supports OTP services across the world. This is the list where OTP service is reliable firebase.google.com/support/faq
Firebase Security is only required for the data you store in the database services such as "Firebase Realtime-Database", "Firestore", and "Firebase Cloud Storage". (It is not required for Authentication)
Here is the information about Security Rules for Firebase: constructfirebase.com/docs/guide-basic/secure-your-firebase-project