How to construct a webinar registration cancel hyperlink?

Hi all,

I’m using the Zoom API via PHP to automatically add a Webinar Registrant. This is working fine:

class AddWebinarRegistrantListener implements Listener
    public function handle(Event $event)
        if ('online' === $event->printer->booking_detail->type) {
            $zoom_helper = IoC::make('ZoomHelper');
            $registrant  = $this->createWebinarRegistrant($event->printer);
            $response    = $zoom_helper->addWebinarRegistrant(

            $event->printer->webinar = $this->storeZoomWebinarResponse($response);

In another listener class, I create a custom email notification for our visitor, because we don’t want to use the standard email that Zoom sends. For our custom email, I need to construct a “cancel registration” link. I’ve checked a few of the hyperlinks in the Zoom emails, and they all seem to have a different hashcode in the query string params. Is there any way to construct this cancel hyperlink myself?

Thanks in advance.

We customize our emails as well and the Cancel link is the only one we cannot recreate in our templates.

The query parameter is the ID of the registrant record, but there is another hash as a path component in the URL which we cannot figure out. Using Django template syntax, we have:{{ WHAT GOES HERE? }}/success?act=cancel&user_id={{ }}

The join URL is provided in the registrant data via the API, but Zoom should also include the cancel URL so no guesswork is required.