The thesis focuses on the development of a web application using Firebase as the backend infrastructure. The application aims to provide a platform for users to add and delete personal transactions. The system's key features include real-time data synchronization, user authentication, and data storage. It includes an analysis of Firebase's capabilities and limitations in building scalable, secure, and efficient web applications. Additionally, the thesis discusses the application's design and implementation, along with testing results, demonstrating the effectiveness of Firebase in building reliable and user-friendly web applications. Finally, the thesis provides recommendations for future improvements and developments of similar web applications.