A DB Visualizer developer designs, develops, and maintains database visualization tools used to manage and manipulate data within databases. They use these tools to create graphical representations of data structures, allowing for easy navigation, analysis, and understanding of complex data sets. Their tasks include writing SQL queries, troubleshooting data issues, and optimizing database performance. They also work closely with data analysts and other stakeholders to ensure that the visualization tools meet their needs, hence facilitating efficient data-driven decision making. Additionally, they might be responsible for updating and improving the software, incorporating user feedback, and ensuring data security and integrity.