Edinburgh Napier University

  During the COVID-19 pandemic, grassroots digital innovations (GDIs) have gained traction as innovation niches, providing an alternative to the prevailing mainstream regime dominating smart city transitions. Drawing upon interviews with experts and promoters of GDIs from 12 European countries, we explore the relationships between these initiatives and mainstream regime actors. Five distinct types of niche-regime interactions have emerged from the analysis: inertia, indirect support, antagonism, direct support, and active collaboration. These interactions do not follow a linear and incremental trajectory, but rather represent dynamic configurations that change over time and at different geographic scales. Consequently, our findings contribute to the literature on socio-technical transitions and grassroots innovation by further revealing the multidimensionality and multiscalarity of mainstream regimes. In light of these findings, we urge scholars and practitioners to reconsider how information flows and power imbalances among local and supralocal actors in mainstream regimes influence the development of innovation niches and dictate the pace of socio-technical transitions.