Login with external webhook/API

I am investigation whether Adalo will work for what we want to do.
We would like to create a mobile app based on an existing web-based system that is powered by MongoDB Atlas, including authentication using MongoDB Realm.
How can I set up the log in in Adalo to authenticate/work with MongoDB Realm?
For example, could we do it via a webhook:

Currently, the users have created an account with MongoDB Realm using either Email/Password or Google Auth:

This is our only main blocker for moving forward with Adalo.

Hey there,

We are investigating the same basically.
I was wondering if you had a solution to it yet

Thanks in advance

I got this to work by creating an api in node that uses the Realm React library to authenticate using a Realm app id. I pass the user email/pwd via External users dialog of Adalo and then obtain a token and user id that I pass back to Adalo