Public participation, including the use of geospatial technologies, is pivotal in planning for sustainability. Contributory participation initiatives, however, face challenges, such as the quantity and quality of the data provided by the public. User-centred applications can address these issues, but since developers often lack understanding of public users, appropriate user involvement in application development processes is crucial. Despite the manifold practices that exist, there is a need to further support user involvement in development processes. This paper contributes to this through findings from three projects aimed at developing applications tailored to the public. Analysing and comparing user involvement in the three projects, several key results emerged. In order to increase developers’ knowledge about public users and to deliver particularly user-centred applications, (i) user involvement should be considered not only in development activities such as requirement-gathering, evaluation and testing, but also in design and implementation; (ii) user involvement can vary in type and extent (i.e. ranging from informative and consultative to participative), allowing user integration in the different development phases; (iii) the combination of process models and design approach, which delivers project-specific development workflows, is suitable for involving users in a project-appropriate and structured manner in development activities.