You can choose to use biometry only for your application. On mobiles users are redirected to the auth page to provide their fingerprint or faceID. On desktop they snap a QR code to open the auth page. Powered by the WebAuthn standard.
Users responding "Yes" or "No" to instantly delivered mobile request in a Messenger of their choice provides simple, yet effective second factor auth. This works well for apps with no vital data. For maximum security add Biometry.
Logintap can be used as the main login factor, in other words the only factor, as most e-commerce shops do for their customers - no other login or password needed. For business data systems a 2FA auth is often needed with or without a password.
A simple addition to the existing SMS one time PINs, that dramatically improves security of sms pins. Users will need to confirm the biometry before seeing the PIN on their phone. No new apps for them, one API call for you.