How does platformization work as vehicle for the integration of public online education into a private global digital infrastructure? And how can education technologies ('edtech') be governed at various levels to benefit the public good? In this article, we examine online environments in primary schools in The Netherlands, a traditionally strong public-school system, where platformization has substantially impacted the precarious balance between private and public interests. Mapping the Dutch edtech landscape, we trace how the integration of digital learning platforms and learning management systems into digital learning environments are propelled by two complementary yet competing strategies: "inter"operability and "intra"operability. We argue that the latter challenges the first. Securing education's public interests necessitates a coordinated governance effort at the sectoral, national and European levels.