A GreenHopper developer is primarily responsible for creating, managing, and enhancing software solutions using Atlassian's JIRA GreenHopper tool, now known as JIRA Agile. They work on Agile project management, creating user stories, issues, and planning sprints. They also configure and manage Scrum or Kanban boards, ensuring efficient workflow. They handle backlog grooming, sprint planning, and tracking progress through burn-down/up charts. Their role also involves developing interfaces, debugging issues, and performing upgrades. They work closely with project managers, stakeholders, and the development team, ensuring effective communication and collaboration. They also provide user support and training.