Public Consultation & Participatory Democracy

The "deliberative democracy" software stack is genuinely mature in 2026, and the leading platforms are FOSS — built by city governments who got tired of paying SaaS vendors to host their public consultations. Pair with Civic Tech Overview, 311 / FixMyStreet for issue-reporting, Forms for the form-tooling layer underneath, and OSS Foundations & Fiscal Sponsors.

Free / FOSS (start here)

• ★ ★ Decidim — AGPL-3.0; Ruby on Rails; built by the City of Barcelona (originally the "Decidim Barcelona" platform, now a federated international project under the Decidim Free Software Association). Used by Helsinki, Mexico City, the European Commission, NYC's "The People's Money" program, and dozens of others. Modules for participatory budgeting, public consultations, citizen assemblies, surveys, debates, and proposals. The default choice for any serious participation platform in 2026.
• ★ ★ Consul Project (formerly Consul Democracy) — AGPL-3.0; Ruby on Rails; built by the City of Madrid in 2015; the original FOSS participation platform. Spanish-speaking world's default; less momentum than Decidim today but still actively developed and broadly deployed in Latin America.
• ★ Loomio — AGPL-3.0; Ruby on Rails; smaller-scale group-decision tool (consensus, proposals, votes). Designed for cooperatives, unions, and activist groups rather than city-scale consultations. New Zealand-based.
• ★ Polis (pol.is) — AGPL-3.0; the "wisdom of crowds" sentiment-clustering tool used by Taiwan's vTaiwan / Audrey Tang's team. Free; participants submit short statements and vote agree/disagree on others — the algorithm clusters opinion groups. Genuinely novel approach to deliberation. Self-hostable.
• Stanford Online Deliberation Platform — research-grade; free for academic use; structured small-group video deliberation.

Paid SaaS (the for-profit flavor)

• CitizenLab (now part of GoVocal) — Belgian SaaS; pretty UI; participation modules similar to Decidim but proprietary; common with mid-size US / EU cities. Paid; not OSS.
• Bang the Table / EngagementHQ — Granicus-owned; the entrenched US municipal SaaS player. Paid.
• OpenGov — paid; a procurement-shaped suite that includes engagement modules.
• Mentimeter / Slido — paid; lightweight live-polling, not full participation platforms.
• Granicus / Civic Plus — paid; vendor-locked municipal CMS that bolts engagement features on top.

Use-case: participatory budgeting (PB)

PB lets residents directly allocate a portion of a city budget. NYC, Paris, Madrid, and Lisbon are the largest deployments.

• ★ ★ Decidim — has the most mature PB module; what NYC, Paris, and Helsinki use.
• ★ Consul — PB was its original use case; Madrid's "Decide Madrid" pioneered the model.
• PBStanford / Stanford Crowdsourced Democracy Team — research-aligned tooling.

Use-case: citizen assemblies / sortition

• ★ Decidim "assembly" module — supports stratified-random selection workflows.
• Sortition Foundation — UK non-profit; provides tooling + facilitation services for randomly-selected assemblies. Paid for facilitation, much of the methodology is openly published.

Use-case: open consultation on legislation

• ★ ★ Decidim — annotated-text consultation modules.
• ★ Consul — same shape.
• Madison (OpenGov Foundation) — an early-2010s annotated-bill tool; archived but historically important.

Honest take (2026)

• Decidim is the clear winner for any city-scale deployment. AGPL means cities can run it without licensing risk; the codebase is mature, internationalized, and accessible.
• CitizenLab is the SaaS escape hatch for cities that don't want to operate Rails. The trade-off is a per-resident licensing model that gets ugly at scale.
• Polis is underrated — its statement-clustering approach genuinely surfaces consensus that Decidim-style proposals miss.
• Hosting matters. Most Decidim deployments are run by the city directly or by partner co-ops (e.g. Codegram in Spain, OpenSourcePolitics in France).

Pick this if…

• City-scale participation, FOSS, fully featured: Decidim.
• Spanish-speaking world / Latin America: Consul.
• You want to surface latent consensus, not just vote: Polis.
• Small group / cooperative / union decisions: Loomio.
• You need a vendor with sales support and don't mind SaaS: CitizenLab.
• You want to see this working in production: decidim.barcelona, decidim.helsinki.fi, peoplesmoney.nyc.