PKMist Hello.
Some answer for you:
1. Are callRecords generated only after the call ends (all participants have left the call) or is there an API to query while the call is active?
A: They are only generated when the call ends and it is the following day. There is no API to view active calls. Microsoft only notifies when the call has ended.
2. Is there an API to get multiple callRecords? The same API will work for you.
3. The granularity of the callRecords is at the session level per participant. Is there a way to get more granular statistics, such as per minute/5 min/10 min? Only the information indicated by the API, therefore, you will need to generate your own statistics.
Please note that this API will not deliver information by call ID when the call goes through an autoattendant, so you will not know what the call tracking is between pstn and Callque or Autoattendant and also the transfers between agents with the previous 2.