This thesis addresses the challenges faced by a stamp-selling company in managing extensive data manually through Excel files, which often led to errors and inconveniences, such as incorrectly input data and time-consuming manual data management. To solve this, a web application was developed using ReactJS for its GUI, Flask for backend development, and Google Cloud SQL for scalable storage. The system integrates real-time WooCommerce synchronisation via webhooks and enforces input validation to prevent inconsistencies. Performance tests demonstrated that the system handles CRUD \textit{Create, Read, Update, Delete} operations efficiently, being able to fetch 2000 stamps in under 200ms, ensuring real-time usability for inventory management and preventing workflow disruptions. Security tests confirmed resilience against attacks such as SQL injections. By replacing Excel sheets with a web-based application, the project not only improves data reliability and performance but also lays the foundation for future scalability and integration with additional business tools.