The teacher opens an app on their phone, holds it up, and takes several photos of the room. Within seconds, the images travel to a cloud server, where a facial-recognition algorithm detects each student’s face, extracts it, and compares it against a database of biometric profiles. The app LRCO Paraná returns a list of names. Students identified in the photos are marked present; those the system does not find are marked absent.

For some students, a false absence is a bureaucratic irritation. For others, it could threaten their family’s access to welfare. In Brazil, eligibility for the Bolsa Família program depends in part on school attendance, and in Paraná such records are now largely generated by an algorithm.