Clubs is a feature currently available on Duolingo's mobile application. It was created for the purpose of learners being able to "connect online and stay motivated". This is accomplished by joining a small group that competes for the highest XP score, while also encouraging one another with an emoji-based chat system.
The current limit for a club group is fifteen members, and one can make their own club or join someone else's using a six-digit code provided by the club admin. The club admin makes decisions regarding who can join, whether they can accept new applications to the club or choose an avatar for the club.