A self-hosted invoicing and project management app with an integrated client portal. Duet is hosted on your own server, which means your data is always private. You can also customise and brand Duet to match your business and its processes. It offers many of the project management features you'd expect including; Kanban boards and task lists; time tracking; discussions and team collaboration; email notifications; and loads more. Unlike many alternatives, Duet has just one up front fee so you can save a lot of money the longer you use it.