How can citizens become active city-makers alongside design professionals, local government institutions and others, by creatively using digital technologies in collaborative processes of urban planning and management? This challenge is particularly daunting in the Buiksloterham, a brownfield area in Amsterdam North, that is assigned as an urban laboratory destined to grow from 200 inhabitants to over 10,000 people. The area was opened to selfbuilders: private individuals and households who build their own home, and collectives of about 15-50 people who build a shared apartment together. The research is based on ethnographic research carried out in the area. It provides a theoretical foundation for understanding the connection between bottom-up city-making processes and institutionalisation. It also proposes a research and design narrative about people-centric hackable smart cities. This contribution results from a long-running research project called The Hackable City (http:// thehackablecity.nl), which between 2012 and 2017 in multiple separately funded iterations, investigated new modes of city-making through the notion of 'hackability'. The project was a collaboration between academics, an architecture and urban design office, and various organisations in the domains of policy, urban services and the cultural field. Keywords Smart cities • Smart citizens • Hacking culture • Urban planning City-making 1 Selfbuilders and Hackable City-Making How do new media and digital culture shape today's practices and logics of citymaking, and what does this mean for the role of citizens? Principles and practices of hackable city-making can be seen at work in the recent resurgence of selfbuilding in Amsterdam, the Netherlands. In the period after the financial crisis, selfbuilding