This article examines the phenomenon of interface governance. It uses two interface technologies—Universal Credit’s digital account (United Kingdom) and ArriveCAN (Canada)—to explore how interfaces and their predictable glitches govern relations between state officials and members of the public. Drawing on tools of government literature, it argues that interfaces do not achieve their stated goals evenly (improved efficiency, digital literacy). Instead, they generate several unintended effects, including heightened bureaucratic intensity, diffused responsibility, and even eroded public trust in state agencies. It urges socio-legal and administrative justice scholars to take interfaces seriously and calls on scholars to adopt socio-legal-technical methods to better conceptualize the effects of infrastructure governance and to imagine other possibilities for public administration.