This article explores the ways in which prisons are imagined as sites of technology development. By attending to expos that showcase prison technologies and constitute “live theatres of technology” (L. Cornfeld, 2018), we carve out ambivalent sociotechnical imaginaries of technological backwardness that are combined with the idea of radical technological innovation to reform the justice system. In doing so, we highlight the prison as one site of technology development and actors at technology trade shows catering to the prison and security sector as platforms for technological mediators that range from corporate prison tech companies to educators as well as representatives of the criminal justice system. The expos emerge as sites where technological development is negotiated through performative sociotechnical imaginaries of prison tech.