Open-source communities — including the global geospatial community that gathers at FOSS4G — keep returning to one hard question: how do you sustain something that is given away for free? The usual answers are donations or commercialization. This keynote session introduces a third reference point the field has rarely examined in depth: the cooperative.

The session does not claim that cooperatives simply "solve" sustainability. Its heart is a genuine tension worth exploring honestly. A cooperative is a bounded solidarity — a defined membership sharing ownership, governance, and surplus. Open source is an unbounded gift — a common good offered freely to everyone, member or not. What can a bounded solidarity teach us about sustaining an unbounded gift, and where do the two part ways?

Three 20-minute talks approach this from different angles. Seki Haruyuki-san (Code for Japan) opens with community-driven open source in practice. Ela Kagel (SUPERMARKT Berlin, Platform Coops eG) speaks on the meeting point of technology and cooperation, and cooperative ownership as an alternative to the extractive platform economy. Lander Jimenez Ocio-san (Mondragon University) brings the empirical and scholarly view of how the cooperative model has worked across seven decades, and where its limits lie.

A 20-minute panel follows, moderated by A.J. Koikoi-san (Eukarya Inc.), exploring democracy and scale, inter-cooperative solidarity and its limits, and how cooperatives live with capital. The session runs in English with Japanese interpretation for the audience.