Here's how you can do it: https://gist.github.com/mrjoes/5189850
Even if this example shows how to integrate CKEditor, the process will not be different from another WYSIWYG editor:
- Create a wtforms widget that provides the necessary HTML for the editor. For CKEditor, this is the class 'ckeditor';
- Create a wtforms field that uses this widget
- Create a new template that will include an editor for JS files (s)
- Flask-Admin, .