• Developed and optimized controllers and services for the calculator system, providing fast and accurate calculations. Used the Spring Framework effectively• Configured the mail client, providing automatic sending of notifications and reports.• Processed and analyzed incoming requests, applying them in the system to optimize work processes. Used the OAuth2 protocol to securely configure configuration files for users.• Conducted regular updates of data in the database, developing and optimizing SQL scripts for safe and effective update of records. This led to an increase in system performance and a decrease in response time.• Actively participated in the process of identifying and correcting bugs, ensuring the stability of the system. Developed a user interface using React, improved the visual experience of users and increased their satisfaction.