Most of the academic research on the developments of EU Justice and Home Affairs (EU JHA) tends to overlook the role played by technologies in their relations with classical 'human' and institutional actors. This is particularly problematic because in official discourses, technologies are requested, designed, and built as cornerstones of European security and its external dimension. Still, apart from 'technicalities', their use and design are generally assumed as politics-free. On the contrary, this contribution brings technologies to the forefront of the research and reframes them in terms of socio-technical assemblages. From this perspective, it analyses the role of the 2011 EU Passenger Name Record project in the making of European security and its external dimension. The lesson learned is that human institutions are neither the only players nor the passive victims of technological determinisms. Rather, focusing on a socio-technical assemblage means to inquire the effective participation of different actors and thus critically discuss the making of European security in terms of politics.