Using webinar API endpoint(s) without creating a marketplace application

Hi together,

I’ve built a custom Zoom integration for a customer of mine. It has already implemented OAuth and needs to use the webinar API to add registrants via API.

Creating, verifying, and publishing a whole app for the marketplace is not feasible, as the integration is custom-built.

How can I use the webinar API for my customer?

Thank you!

Best, Max