Dutch public organisations are pioneering the construction of PubHubs, a new decentralised open source social network for the public sector. In conjunction with two universities, the PublicSpaces coalition is exploring what form PubHubs should take, considering not only technical aspects and software design, but also moderation and governance. During this session, the software developers from Radboud University will show what has been designed and built so far. Utrecht University will present approaches to safeguarding public values in PubHubs. Public broadcaster VPRO and the Bibliotheek Midden-Brabant will present the results of their recent PubHubs hackathon.