Worked on the mautic/mautic repository to enhance the reliability of email campaign export and import workflows. Addressed export failures by introducing null-safe handling for parent references and allowing null values in variant settings, which reduced data loss and improved robustness when exporting campaigns. Expanded functional test coverage for the EmailImportExportSubscriber, ensuring that export functionality correctly handled parent-child relationships and variant settings. Focused on backend development using PHP and Symfony, with an emphasis on testing and unit testing practices. These improvements enabled faster and more reliable delivery of customer email campaigns while increasing the maintainability and reliability of the codebase.