Storing an authoritative copy of data on the users’ devices enables offline work and stronger data ownership [1], and synchronising updates through a P2P network should allow the same kind of real-time collaboration that we know from cloud software. This application fits well with the principles articulated in Design Principles: the data in this software belongs to the user, and there are essentially no restrictions as to what the user may do with their data. By storing data in the Automerge CRDT, replicating it over a peer-to-peer network based on Dat, building user interfaces using React’s FRP model, and delivering the software as an Electron application, PushPin has met these goals.