Polygloss target audience: Intermediate level
Polygloss pedagogical approach: Producing content in language
Same target audience, same approach
Yask: https://yask.app
(learned about this app very recently, it's a fairly new app, but older than us in existence, turns out we are quite similar to them in approach, maybe not as much in what we implement and the marketing)
Same target audience, different approach
Clozemaster: https://www.clozemaster.com/
Different target audience, same approach
HelloTalk: https://www.hellotalk.com/
Tandem: https://www.tandem.net/
Hinative: https://hinative.com
Skritter: https://skritter.com/