✅ The client, one of the most valued energy companies in the world, constantly improving their microservice-based software suite, with a focus on enhancing existing functionality and developing new features to meet user requirements• Designed and implemented a dynamic API solution, empowering users to filter and sort data efficiently with extensive filtering options, akin to an Excel-like filtering experience.• Designed and implemented a high-performance hierarchical tree traversal and searching algorithm for large datasets with thousands of entries. The optimization led to improved application performance and responsiveness.

✅The client, a multinational financial technology company that provides payment technology and services to merchants, issuers, and consumers, was facing challenges in competing and losing major clients to competitors on the global market due to a lack of features and performance issues in their system.• Implemented and integrated various payment-oriented solutions (such as 3DS2 Authentication, Open Banking, DCC, etc.) using Java 8 and Spring Boot. This ensured competitiveness in the global market and resulted in annual revenues exceeding 100M.• Enhanced payment page capabilities using JavaScript, AngularJS, jQuery, Thymeleaf, and Bootstrap to capture GDPR-compliant billing and shipping details, resulting in a 3M annual sales increase.• Automated the testing of the development environment to ensure system's robustness by creating pipelines using Groovy and Jenkins, thus avoiding the burden of manual troubleshooting, boosting productivity for developers and testers.• Using Kibana, prepared monitoring plans and dashboards at every production rollout, thus being able to early detect unexpected errors and performance issues.• Developed a PCI-compliant migration tool in Java 8 and Spring MVC to transition users from 3DS1 to 3DS2 within a tight deadline, preventing 30,000 monthly fines imposed by EU legislation.

• Contributed to the development of both the database and application designs, as well as implemented them, resulting in efficient and user-friendly systems that significantly improved the company's operation