Participatory budgeting (PB) is currently one of the most widely adopted democratic innovations. ICT platforms are key enablers of PB processes, by supporting citizen engagement. They support the establishment of diverse participation channels to build candidate proposals, for the voting process, and for monitoring proposals' implementation. PB platforms differ from electronic voting systems, reflecting the intrinsic nature of PB processes. While vote secrecy and trustworthiness of voting results is still a major requirement, other factors weight in, such as the focus on the whole process and the need for engaging several citizens by providing multiple participation channels. PB processes take place at multiple scales (municipal, national) requiring flexible deployment and dimensioning approaches. EMPATIA is an ICT platform for PB, based on multiple dimensioning and deployment options that reflect the scenarios where PB tools are expected to operate. The evaluation results provide relevant inputs to the design and implementation of similar participatory and/or voting platforms.