Headless Appian Authentication using Web API

Hello there,

We are trying to implement the headless BPM. All users are associated to appian accounts but we need to validate the user login screen (not from appian), password reset etc on REACT WEB using API call. Now for that, we are in need the endpoint URL/smart service(which can validate the basic authentication using username/password based on group created in appian) for login authentication for typical appian login form/screen.

can someone help me on the same please ?

Note : This is on cloud instance and not on-premise/self managed servers.