I'm developing a consumer mobile app and was planning to have these options in the registration:
Mobile number or email
Password
Or, use one-time passcode [instead of password]
Continue with Facebook
Continue with Google
Continue with Apple
Continue with Instagram
So the user has the option of using mobile number or email (just like Facebook, Instagram, and Twitter do), and they also have the option of using a password or a one-time passcode instead of password.
Question:
From a user expectations perspective, is it unusual and therefore potentially confusing to offer for sign-up a one-time passcode as an alternative to using a password, instead of offering only one OR the other? Conceptually, I think it would be like offering users BOTH the option of traditional sign-up/login AND "magic-link" sign-up/login.
Just to give some further context, it would also be my intention to let those who opt for a password to receive a one-time passcode instead of using their password for any given login session, and it would be a one-time passcode rather than a password reset. So the login screen would as for "mobile number or email" and "password" or offer to "Send one-time passcode". (Someone who never signed up with a password would obviously use the one-time passcode option.)
Thank you.
EDIT: elaborating here with four use cases for clarity.
1. For users who prefer email and traditional login: Register with email and password. Verify email ownership via email. Log in with email and password, or request one-time passcode if forgot password (more convenient than having to reset password).
2. For users who prefer email but don't like having to remember passwords: Register with email and one-time passcode that gets emailed to the user. Verify email ownership with passcode. Log in with email and one-time passcode.
3. For users who prefer mobile number and passwords: Register with mobile number and password. Verify mobile number ownership via SMS. Log in with mobile number and password, or request one-time passcode if forgot password (more convenient than having to reset password)
4. For users who prefer mobile number and don't like having to remember passwords: Register with mobile number and one-time passcode that gets texted to the user. Verify number with passcode. Log in with mobile number and one-time passcode.
I think someone who registers with mobile number likely prefers a one-time passcode instead of a password, so it may not even be necessary to offer them the password option, but I don't think someone who registers with email necessarily prefers a password, so they could use a password or a one-time passcode.
