onboarding backend solutions for adding to base44 user table in DISC-Q app - a private app

My app is private is meant to onboard staff directly and send custom invitations to join the app -I noticed that onboarding staff is only possible through base44 invitations. This breaks my workflow as my front end cannot add to user database. -is there a backend function (URL, API) i can access to add users to base44 user database directly

• im sure im not the first one with private onboarding - so if not whats your best practice recommendation for adding users directly - also as bulk.

• if not, then can your team develop a solution for this or at least suggest third party services for streamlining private onboarding