Meeting.participant_joined event arrives before meeting started

A clear and concise description of what the question is.
Basically, I’m creating an app which gets webhooks from Zoom regarding when a meeting starts or ends, and when participants join and leave. On occasion, the webhook for a participant joining comes before the meeting actually starts, which then messes up our code. Is there a way to prevent this from occurring? (Ex: reject the participant joining webhook and make it come back later). I need to have every participant in my records.
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Which App Type (OAuth / Chatbot / JWT / Webhook)?
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I am building an OAuth app which requires Webhooks from Zoom.
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Hey @22ap0894,

Thank you for reaching out to the Zoom Developer Forum. When you see this issue, do you have the waiting room enabled? If so, please test if disabling the waiting room changes the behavior to what you expect.


The waiting room was disabled, but for future meetings once in production, the waiting room might be enabled.

Hey @22ap0894,

Would you be able to share a meeting ID where you saw this issue? I’ll look into it further.


The meeting ID was 943 0656 7459.

Hey @22ap0894,

Thank you for providing that meeting ID. I’m seeing that in every instance except for one, that meeting only had one attendee and that was the host. In the one exception, there were two attendees scheduled but I’m not seeing that either joined. Is there perhaps another meeting that has more attendees that exhibits the issue?

In regard to how to prevent Webhook events before the meeting starts, you’ll want to make sure that you’ve disabled the Waiting Room as well as ensure that Join Before Host is disabled.

I hope that helps!


Unfortunately, I don’t think I have another meeting with more than 2 participants. However, in any case, wouldn’t the Meeting Started notification still come before a Participant Joined notification, since the participant can only join a meeting that has started? In the case of the host, I would suppose this to also hold true.

Hey @22ap0894,

This is a great question! If you have Join Before Host enabled, this will actually allow participants to join before the meeting starts which means that the Meeting Started event won’t be triggered. When the host joins, the Meeting Started event should be triggered.


One option is to use the Participant Joined Before Host webhook to see if users have joined before the meeting start.

Let me know if that helps.


Ok thank you. What about the Waiting Room w/o Join before Host? If people are in the waiting room then they haven’t joined the meeting yet right? So why would the participant join webhook come before the meeting start? This was the setting for the meeting for which I tested, it said that I (the host) joined before the meeting started, even though Join before Host was off.

Hi @22ap0894,

Do you have an example payload you can share? We’re happy to take a closer look at a specific example.


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