Wekan
The closest open-source, self-hosted match to Trello's own card-and-list model.
Wekan is a free, open-source Kanban board that deliberately mirrors Trello's UI: boards, swimlanes, lists, and cards with labels, checklists, due dates, and attachments. It self-hosts via Docker, a Linux Snap package (with automatic updates), or from source, and stores everything in MongoDB you control. It even ships a dedicated Trello-import tool for migrating existing boards and attachments.
Strengths
- +Free MIT license, no per-seat cost ever
- +UI and workflow are the most Trello-like of any open-source option, so the switch is low-friction for a team used to Trello
- +Dedicated Trello JSON/attachment import tool eases migration
- +Active project with regular releases and a large, engaged community (20k+ GitHub stars)
Trade-offs
- −Interface is functional but less visually polished than Trello's current design
- −Advanced reporting/analytics views are limited compared to Trello Premium
- −You are responsible for your own backups, updates, and uptime once self-hosted
- −MongoDB dependency adds a small extra piece of infrastructure to operate versus a single-binary tool