is the Barcelona City Council digital participatory platform for building a more democratic city. It is written in open code so any citizen can see how it is built and reuse or even improve it. It is also a tool for building a network of more open, transparent and collaborative cities empowering citizens. aims to acting as both a portal and infrastructure for the participatory processes promoted by the City Council (PAM, implementing regulations, urban-development plans etc.,) and those started by citizens and associations (commons initiatives, community development, etcetera). Developed by means of free software using open, flexible and participatory methods, the platform offers collective tools for decision-making, communication and campaigns, calling in-person meetings, collaborative text-writing and other digital communication and collaborative functions for improving the democratic quality of the City Council and other organisations.

Decidim expanded in February 2017. An agreement was signed by the Barcelona Provincial Council and six metropolitan municipalities (Hospitalet de Llobregat, Terrassa, Sabadell, Badalona, Gavà and Sant Cugat del Vallès), the Barcelona City Council and Localret consortium to extend Decidim to the other Catalan municipalities. More municipalities then signed. For example, Pamplona and Vilanova i la Geltrú now have an operational Decidim platform.