ClassDojo is one of the world's most successful educational technologies, currently used by over 3 million teachers and 35 million children globally. It reinforces and enacts emerging governmental "psycho-policies" around the measurement and modification of children's social and emotional learning in schools. This article focuses specifically on the ways ClassDojo facilitates psychological surveillance through gamification techniques, its links to new psychological concepts of "character development," "growth mindsets" and "personal qualities," and its connections to the psychological techniques of Silicon Valley designers. Methodologically, the research mobilizes network analysis to trace the organizational, technical, governmental and scientific relations that are translated together and encoded in the ClassDojo app. Through its alignment with emerging education psycho-policy agendas around the measurement of non-cognitive learning, ClassDojo is a key technology of "fast policy" that functions as a "persuasive technology" of "psycho-compulsion" to reinforce and reward student behaviours that are aligned with governmental strategies around social-emotional learning.