In the past decade, the open-source model has been adopted across industries, including the construction industry. By packaging functionality in publically available libraries, a collaborative model for innovation is created. As geotechnical site investigations produce large amounts of measurement data in various formats, working with open-source tools can help to better process, visualise and interpret data. Collaboratively developed packages can lead to a more uniform workflow for subsequent interpretation tasks and foundation engineering. This mini-symposium targets the (aspiring) developers and contributors to open-source packages for geotechnical site characterisation. Application including but not limited to processing of standardised data files, interaction with webservices, visualisation of ground data and interpretation of geotechnical site investigation results can be covered. The intention is to create a forum for geotechnical engineers with an interest in open-source development to share ideas and discuss the future of collaborative development for site characterisation.