Duet vs Wekan: What are the differences?

Duet: Project Management for Freelancers and Small Businesses. Duet is an intuitive project management app created specifically for freelancers and small businesses. Duet does not have a monthly fee. Instead, it is available for a one time fee of $49; Wekan: The open-source Trello-like kanban (built with Meteor). Whether you’re maintaining a personal todo list, planning your holidays with some friends, or working in a team on your next revolutionary idea, Kanban boards are an unbeatable tool to keep your things organized. They give you a visual overview of the current state of your project, and make you productive by allowing you to focus on the few items that matter the most.

Duet and Wekan can be categorized as "Project Management" tools.

Wekan is an open source tool with 14.6K GitHub stars and 2.13K GitHub forks. Here's a link to Wekan's open source repository on GitHub.