We have a requirement to have a user profile with multiple aliases along with username to login. That means user can use alias (can be stored in user metadata) to login. So use can use username/email/alias to login.
How can we implement this & how we can ensure that alias is unique cross db & username field ? I saw this custom database option, but do we need to host our own database & then will option to control this login verification?
Alias is not supported by Auth0 for login purposes. You can use a username or email to login.
If you would like to use an alias a custom UI + Custom DB would be required. This implementation has many limitations and it defeats the purpose of using Auth0. The use of Custom DB scripts is used as a temporary solution until users are migrated across to Auth0. I would highly recommend reconsidering the use of aliases.