This repository contains a comprehensive list of 117.981 free and disposable email providers
ProtonMail.com is a free email provider. Why would it not be on a list that contains free email providers? Gmail.com and Outlook.com are also on here, because they are also free email providers.
ProtonMail.com is a free email provider. Why would it not be on a list that contains free email providers? Gmail.com and Outlook.com are also on here, because they are also free email providers.