A Platform for Participatory Budgeting – Participatory budgeting processes are among the most illustrative, real-life experiences of participatory democracy. Participatory Budgeting (PB) has its beginnings in the late 1980s, when some Brazilian cities started to experiment with processes of citizen participation in decisions about how to better allocate part of the city’s budget. Although PB takes different forms, they can all be considered as refining the following base process: residents of a city propose spending ideas, volunteers or delegates develop those ideas into proposals, residents then vote on the proposals, and the government finally implements the winning projects. Since the 1980s, PB processes have spread around the world as a set of administrative reforms and, more recently, as a ”best practice” in mainstream international development. AppCivist-PB customizes the AppCivist platform for PB. It specifically aims at enabling city governments to configure the software assemblies that best match the requirements of the kind of PB campaign they want to support, while leveraging existing software services and components. However, from the overall perspective of participatory democracy, the goal is primarily to facilitate the elaboration of proposals by citizen assemblies that form according to the citizen interests. In practice, AppCivist-PB helps users assemble proposal making and selection workflows, using service-oriented architecture (SOA) principles. The composition principles of SOA allow for various implementations and instances of these workflows. The AppCivist-PB platform was developed in collaboration with the Social Apps Labs at CITRIS at University of California Berkeley (USA) in the context of CityLab@Inria and Inria@SiliconValley, together with the support of the EIT Digital CivicBudget activity. AppCivist got awarded the UC Berkeley Chancellor’s Award for Public Service 2016-17 for Campus-Community collaboration with the City of Vallejo.