At this time our customers can choose from one of our pre-designed templates or import their own HTML. VerticalResponse caters to people who want responsive email templates, meaning they will adapt to whatever size screen the email is opened on. This is especially useful because of the increasing use of mobile devices to open emails. Providing the ability to edit the HTML code with a WYSIWYG editor could compromise the responsive functionality. We may explore the possibility of implementing a WYSIWYG editor later, so keep an eye on our announcements!