As the fortification of Europe's borders and its hostile immigration terrain has taken shape, so too have the biometric and digital surveillance industries. And when US Immigration Customs Enforcement aggressively reinforced its program of raids, detention, and family separation, it was powered by Silicon Valley corporations. In cities of refuge, where communities on the move once lived in anonymity and proximity to familial and diaspora networks, the possibility for escape is diminishing. As cities rely increasingly on tech companies to develop digital urban infrastructures for accessing information, identification, services, and socioeconomic life at large, they also invite the border to encroach further on migrant communities, networks, and bodies. In this book, Matt Mahmoudi unveils how the unsettling convergence of Silicon Valley logics, austere and xenophobic migration management practices, and racial capitalism has allowed tech companies to close in on the final frontiers of fugitivity--and suggests how we might counteract their machines through our own refusal.