The making of digital public infrastructure

This thesis investigates how a digital infrastructure becomes a public thing. The question is approached through the case of Pix, the instant payment system launched by the Central Bank of Brazil in November 2020, which within five years reached 76% of Brazilian adults, surpassed credit and debit card volumes in 2023, and became the object of constitutional amendment proposals, presidential interventions, and diplomatic defense in international trade dispute. By every criterion the literature on digital public infrastructure articulates, Pix delivered. What the literature did not anticipate, and what this thesis theorizes, is what such an arrangement produces when the promise is fulfilled. Drawing on an abductive, interpretivist methodology that combines documentary, ethnographic, and experiential data collected between 2020 and 2025, and on the lineage of material politics from Dewey through Marres, Latour, and Honig, the thesis argues that a digital infrastructure becomes a public thing through a process it calls publicization. The process articulates two constitutive operations — sovereign inscription, through which sovereign authority fixes interdependent and non-circumventable properties at the architectural level, and delegated enactment, through which the operational realization of those properties is routed through a field of market intermediaries — and unfolds as a cycle of politicization and stabilization driven by the re-description of inscribed properties as they are displaced across domains. The thesis contributes to three bodies of literature. To Information Systems scholarship on digital platforms and infrastructures, it exposes the presupposition that architectural closure is emergent, and develops the vocabulary for arrangements whose closure is constitutive. To the tradition of publics and public things, it articulates publicization as the process through which sovereignly inscribed arrangements become objects of democratic attachment. To the policy literature on DPI, it argues that the administrative criteria around which the field has converged are necessary but insufficient. Publicization names a destiny for digital arrangements at population scale distinct from platformization, already underway in Brazil and offered here as a framework for reading it elsewhere.