In the API doc, the AddUsernamePassword marks both username and email as required. This is not something I consider good user experience as both fields are required to be unique, but I can work around that by generating a random username and let the user fill in the email.
But, I noticed that RegisterPlayFabUser allowed me to either specify username OR email, which is inconsistent with AddUsernamePassword.
And then there is LoginWithEmailAddress which user can sign in with email, but no Login APIs with username seem to exist. Eh??
Links to the mentioned API:
Answer by SethDu · Dec 30, 2019 at 05:57 AM
In terms of AddUsernamePassword request, please feel free to send a thread on Feature requests forum and votes from developers in the community can help with the priority.
Moreover, to use Username to login, please see the usage of LoginWithPlayFab.