WHMCS - WHMCS is an all-in-one client management, billing & support system for online businesses.

Brainscape - Find, create, and study SMART FLASHCARDS on any device. DOUBLE your learning speed using the most effective study system on the planet. Keep all your content in sync across Brainscape's website and your Android devices.

HostBill - HostBill is a powerful and flexible, all-in-one automation, billing, client management and support platform for online businesses.

Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.

Blesta - Blesta is professional client management, billing, and support software.

Upmind - Client management and billing for service businesses.