Public - Group chats.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
nocnoc - Instant group chat invite via link
Clever - syncing between education applications for K-12 schools
Viber Communities - Group chat with up to 1B members, admin controls and more
Claroline - Claroline is a collaborative eLearning and eWorking platform.