I would like to build a bit of custom code around geonetwork where I want to reuse existing database from gn. For my usecase it would be nice if users could register on a custom site and then use the credentials as their geonetwork login.

Now, instead of reinventing the wheel when writing all the neccessary tables like users, groups, email, etc. it would be helpful to have API access to those functionality.

The closest I found is this. So it's likely, something similar exists, but seems to be undocumented.

Does anyone know, how to access user creation functionality as is done when registering on the geonetwork-ui?