The creation of new users can be done by a webservice you create and where you talk to from another program. The use r roles can be done there also or create a special operation to set / change the user roles of an account.
For Login authentication I would go for some SSO option. There is a SAML module in the appstore you can use.
There are different ways to do this, SAML SSO is the most used afaik. The next link gives an overview of the possibilities:
This one can be useful too: https://docs.mendix.com/developerportal/deploy/mendix-sso
I hope this helps.
Hi, you can try for some SSO option and then manage your privilege. Thanks