Webhooks: participant_join event does not contain registrant_id

We are trying to utilize webhooks (using the marketplace) for the events of a participant joining and leaving a meeting, in order to display live meeting information in a web app that we are building.
We have used the Add Meeting Registrant API call to add a participant to a meeting. The call has returned the registrant_id and the join_url for this participant.
After hitting the join_url and joining the meeting, the meeting.participant_joined event returns NULL in the participant.id field.
On the contrary, when the participant leaves the meeting, the meeting.participant_left event returns the expected value in the participant.id field, matching the registrant_id that we received when we added the participant to the meeting.
This is inconsistent on the one hand, but more importantly, it does not allow us to identify the participant who connects to a meeting in real time. The Retrieve Meeting Participants Dashboard API call, only returns the information correctly (including ther registrant_id) after 30 to 60 seconds.
Could you please try to reproduce this and let us know if it is a known bug? Any further information on workarounds or possible fixes is welcome.

Hi @apochr,

Could you let us know what is the meeting ID, participant.id and registrant_id field so that we can take a closer look?

I’ll take a look at the Dashboard API as well, it should be almost instant if not a couple seconds delay.


Hi Michael,
Meeting ID was *********** and the registrant_id we received from the Add Meeting Registrant API call was “w0Y6oRXDSBmdNOdtZfZgFg”. This string appeared as expected in the “participant.id” field of the meeting.participant_left event, but the same field was NULL in the meeting.participant_joined event. For testing, we hit the join_url from a browser.
Thanks for looking into it,

*This post has been edited to remove any meeting / webinar IDs

Hi again, I might be wrong about the Dashboard API call (Retrieve Meeting Participants). We tried to reproduce the problem today and it worked with a max 4-5 second delay. That could help in identifying programmatically who entered the meeting, after having received the join event, but it is not a consistent solution (a participant joining and leaving almost immediately would break the application logic).
So let’s keep the inquiry about the NULL value of “participant.id” in the meetings.participant_joined event.