Decidim update: What to learn from nearly a decade of digital citizen participation legacy

Across the past decade, a “deliberative wave” – as described by the OECD – has swept through cities and institutions worldwide, driven by digital technologies and civic innovation. Yet in times of democratic fatigue and growing discontent, cities face the challenge of maintaining trust and engagement while navigating rapid digital transformation.

Nil Homedes Busquets, Director of Decidim, explored how the open-source digital platform, originally developed by the City of Barcelona, has evolved from a local civic project into a global infrastructure for participatory democracy. Nearly a decade after its creation, Decidim is now used by more than 450 organizations worldwide – from municipalities to cooperatives and civic movements – enabling citizens to collectively propose, debate, and decide on public policies within a transparent, inclusive, and democratic framework.

Its success lies in a modular architecture, structured around participatory spaces (where participation takes place, such as budgeting or consultations) and components (tools for proposals, meetings, surveys, or accountability). This modular building system lets institutions configure Decidim to their specific needs, ensuring flexibility and scalability.

The hybrid participation model bridges digital and in-person deliberation: citizens can attend meetings, submit proposals online, and track how decisions are implemented, making governance more inclusive and transparent. To build trust and security, Decidim integrates AI-assisted moderation, identity verification, and open APIs for connecting with other civic systems – even exploring links to urban digital twins for evidence-based policymaking.

Its governance structure stands out as a public-commons partnership. Maintained by the Decidim Association, an independent, community-led organization, the platform exemplifies how digital infrastructures can be jointly managed by governments and civil society as shared public goods – strengthening digital sovereignty and long-term sustainability.

Recent updates include informal participation features, co-authored proposals, and a read/write API, broadening functionality and inclusivity. Local communities worldwide – from Europe to Japan and Latin America – continue to adapt Decidim to their cultural and linguistic contexts, showing how open collaboration can scale globally without losing democratic integrity.

Decidim demonstrates that digital participation can remain citizen-owned, transparent, and trustworthy when technology is governed democratically. The platform embodies a new understanding of how digital infrastructures can serve the public good – not as tools of efficiency, but as enablers of collective intelligence, openness, and civic empowerment. By linking participation with innovation and accountability, Decidim offers a compelling vision of how cities can strengthen democracy and public trust in the digital age.

This event is part of the ISCN Global Mixer, a series of events organized by the International Smart Cities Network. The presentations cover a wide range of topics related to international smart city approaches and provide exciting insights into urban digitalization worldwide - in just 30 minutes.