Chat for not registered users

We have to implement a one-to-one chat in our application, so we need to know if we can use Zoom Chat APIs for this feature, but we need even not registered zoom users to use this functionality and chat with others not registered users.

So for the user scenario will be as follow: - He registers in our custom app → login → go to chat → search for a registered user in our custom app → chats with him using zoom.

Is it possible to do it for more than 1000 users or we would need a specific license?
Thank you