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Hey! Does anyone know if there is a way to remove e-mail as a mandatory input? Our platform notifies users through WhatsApp as a few of them do not use e-mail.

So you would like to disable all emails as well? 
There is a way to make email optional but <http://cal.com|cal.com> rely on having email address. May be you can set a dummy email for now. 

You should be able to make email optional in getBookingFields.

No one has done something like this AFAIK

<https://github.com/calcom/cal.com/blob/main/packages/features/bookings/lib/getBookingFields.ts#L169|https://github.com/calcom/cal.com/blob/main/packages/features/bookings/lib/getBookingFields.ts#L169>
You can prefill a dummy email if needed using email query param