This paper presents SPOC, a system that is meant to promote the sharing of physical objects in local communities, while ensuring the traceability of these objects. Following the principles of local-first software and grassroots applications, SPOC preserves the sovereignty of the users over their data, as these data are only stored and processed locally on each user’s device (typically a smartphone). No Internet connectivity is required: the users’ devices only interact pairwise via short-range D2D transmission technologies when exchanging credentials, when an object is handed over from one user to another, or when two users decide to synchronize their devices.