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.
Shorten.REST - A URL shortener API you can depend on
Clozemaster - Learn a language through mass exposure to useful vocabulary in context.
PixelMe - URL shortener for savvy marketers
Busuu - Join the global language learning community, take language courses to practice reading, writing, listening and speaking and learn a new language. Learn English with busuu's .
Pixela - Record and Track your habits or effort. All by API.