By listening to its core audience--teachers--ClassDojo's educational software has reached 90% of U.S. schools. Now the real work begins: how to get someone to pay for it.

With a staff of less than 30 and $31 million* in funding, ClassDojo has quietly grown into one of the most popular technology tools in K-12 education. Teachers use the free ClassDojo mobile app to ...

1 of 2 ClassDojo co-founder and CEO Sam Chaudhary poses among his employees working Wednesday afternoon, May 11, 2016, in San Francisco, Calif. (Karl Mondon/Bay Area News Group) ...

Starting in January, ClassDojo will store student profiles for only one year. ClassDojo is a classroom management system designed to help teachers improve student behavior.