A: Hi Marcel,

By default, multiple users can join the call. However, if you want to customize APIs to allow only 2 users to join the call, then you will need to write a custom logic in your code base.

For this customization, you will require one REST API from VideoSDK, through which you can check how many participants are there in any roomId, at any point of time.
https://docs.videosdk.live/api-reference/realtime-communication/fetch-active-participants

Hope this satisfies your query!