Memrise is a language learning platform available in iOS, android, and web. It has more than 150 language courses across 25 languages. The app has over 20 million registered users, all courses are totally free to learn, and there is no advertising. There are extra features and learn modes that can be unlocked with a Memrise Pro subscription.
Memrise has been profitable since late 2016.
Founders: Ben Whately, Ed Cooke, Greg Detre