Over a two-month period, contributed targeted backend improvements to the shopsys/shopsys repository using PHP, SQL, and Symfony. Developed a feature that enhanced blog URL generation by skipping translations with null names, which prevented broken URLs and improved SEO reliability. In the following month, focused on security by implementing referer URL validation within the social login workflow, addressing an open redirect vulnerability and ensuring only valid referer URLs are accepted. Additionally, improved code clarity by renaming session constants. The work emphasized business value, maintainability, and security, demonstrating a methodical approach to backend development and code quality in a production environment.