Webinar - Registration Limit

In the Zoom Webinar UI, there’s the ability to set the number of registrants on a given even. (see screen shot)

In our web apps, we would like to hide any webinar who’s webinar is at the registration limit, but:

1 - It doesn’t look like this value is available via the API - https://marketplace.zoom.us/docs/api-reference/zoom-api/webinars/webinar.

2 - When I trying to register for a webinar that is at (or over) the registration limit, I receive a generic “400 - bad request” error.

Is there anyway with the API to determine the registration limit? And any plans to implement a better response code when trying to register for a webinar that has exceeded it registration limit?


Hey @nyoumans,

As for seeing how many participants are in a webinar this endpoint may help. https://marketplace.zoom.us/docs/api-reference/zoom-api/dashboards/dashboardwebinardetail

It has a participants field which lists the number of participants in the webinar.

Let me know if that helps :slight_smile:


Thanks, but I have no problems pulling a registration list, the issue is:

a) seeing if a specific Webinar has “Restrict number of registrants” set
b) getting the “Bad Request” error when registering an Attendee when the “registrant limit” has been reached

The registration limit will vary per Webinar and I while I can work-around this if I have to, it would preferable if the registration limit was visible with the API. A more “freindly” error message would be helpful as well.

We are migrating from WebEx to Zoom and the registration limit is easy enough to retrieve with the WebEx API.


Hi @nyoumans, pardon the delayed response.

We do have the ability to add/manage Webinar registrants via API (which could be used alongside logic for restricting number of Registrants) - but do not currently provide the ability to restrict the number of registrants directly with the API. That said, I’ll add this in as a feature request to our update schedule.

We’re also actively working on improving our error code messages, and appreciate you flagging this one. I agree this can be improved to be more helpful.

Let us know if you’re still working to implement this, and if we can be helpful.


You can now Set and Get a Webinars registrants_restrict_number (in the settings object).


Hello, I’m not a programmer, I’m trying to understand the UX flow for a registrant. While I want to cap the registration for the webinar at 100, I’d like for the potential registrant to receive a notification that registration is full or have that person go ahead and submit a registration so we can capture contact information, but then receive an automated email that the event is full. Also, although I’ve capped the registration at 100, it’s not showing up that in the Invite Webinar section which can be confusing. Especially when going off of a webinar template.

Hey @ariana.ward,

This would need to happen on your end with custom code.

Even if the Webinar is limited to 100 attendees, Zoom still allows unlimited people to register for it. But out of those unlimited people, only the first 100 who join will get in.


Like @nyoumans I need to know when a webinar or an webinar occurrence is fully booked.

We are showing all our webinars and occurrences on our websites and I want to hide the ones fully booked.

Right now, like in july 2019 when @nyoumans asked, is no information in the response object, neither in the webinar nor in the occurrences object.

Like @tommy wrote a registrants_restrict_number is available but that’s it. For getting the number of registrants I would have to make a request for every occurrence with: /webinars/{webinarId}/registrants

But this is unpractical as too many requests could happen and the pro account has a rate limit of 20 and the others 60 requests/second for this type.

I would therefor like to suggest and also to request to add this information to the existing responses.

For example for a webinar of type 9 in the occurrences object:

"occurrences": [
    "occurrence_id": "1592125200000",
    "start_time": "2020-06-14T09:00:00Z",
    "duration": 60,
    "registrants":  20,  // <-- with that info we could also calculate remaining seats
    "status": "available" // <-- would be great to get "booked" or "full"

Do you see any chance to implement something like that?

Hey @Silva,

You will need to do as you said, Get the Registrants for Each webinar.

Or you can use our Registrant Created Webhook and count them yourself.