The era of diversity is now behind us. Our new reality is characterized by superdiversity, especially in urban areas. Superdiversity also challenges us to rethink schemes and practices of solidarity. Where the welfare state was based on explicit and implicit notions of shared community and citizenship, superdiversity now confronts us with the question what we still (want to) share? The project DIEGEM is based on action research together with a range of ‘users’ from civil society, on four societal domains: ‘learning’, ‘working’, ‘public space and housing’ and ‘free time’. Four pilot cases followed by action research cases provide the methodological foundations for the project that question the relation between solidarity and diversity.