Solidarity in Development: Participatory collaboration and open source development in the Amazon All open source software has a development story. This session teaches participatory development, which teams can use to improve the quality and immediate impact of open source software. We will cover how to get started with participatory development, how this approach differs from typical open source software development, and we will discuss an example of how our team uses it in practice. Using a story based approach, we will share how our process endeavors to infuse principles of allyship and human-centered design as we co-develop GIS tools with communities on the frontlines of ecological and climate crises, to assert their environmental rights. This session features a chapter in the Mapeo development story when Mapeo Mobile v2 finally is put in the hands of the land defenders who inspired some of its unique features: offline first functionality, peer-to-peer GIS data distribution, customizability, and ease of use for new users of digital technology. Digital Democracy has been breaking down the barriers between software development and the people most in need of innovative technologies by investing in programmatic technical accompaniment and bringing our developers to the remote regions where accessible GIS tools are needed most. Join Jen Castro and Karissa McKelvey as they share the technical story of customizing Mapeo for a community monitoring project in Northern Peru and how we managed real-time collaboration on development in a small town with very limited internet access. Authors and Affiliations – Digital Democracy Track – Software Topic – FOSS4G implementations in strategic application domains: land management, crisis/disaster response, smart cities, population mapping, climate change, ocean and marine monitoring, etc. Level – 2 - Basic. General basic knowledge is required.