A Jira developer works with Atlassian's Jira software, a project management tool used for issue tracking and workflow management. They customize Jira according to company needs by developing new plugins, scripts, and workflows. They also maintain and optimize the existing Jira system, troubleshoot issues and provide technical support. Additionally, they collaborate closely with project managers and team members to ensure the software effectively supports project tracking and management. They often have a deep understanding of Java and other programming languages, as well as strong problem-solving skills and a good understanding of project management methodologies.