Koma-Mail is described as 'email client which is comfortable and has very handy functions. It does not need an installation, so that you can run Koma-Mail from your flash drive but, of course, also on your desktop' and is an app in the Office & Productivity category. There are more than 50 alternatives to Koma-Mail for a variety of platforms, including Windows, Mac, Linux, Android and Android Tablet. The best alternative is Thunderbird, which is both free and Open Source. Other great apps like Koma-Mail are Google Calendar (Free), K-9 Mail (Free, Open Source), Microsoft Office Outlook (Paid) and Mailbird (Paid).