GanttProject is free Java based, project management software that runs on the Windows, Linux and Mac OS X systems. Developed by Dmitry Barashev, Alexandre Thomas
License: Open Source
Paymo is a versatile project management tool with strong time tracking and invoicing capabilities, making it ideal for freelancers and small businesses. In contrast, GanttProject excels in project planning with its robust Gantt chart features and resource management, catering more to users focused on detailed scheduling and task dependencies.