B2B with over 1k clients – Rebuilding a legacy monolithic application using EJB and WebLogic with a modern technology stack· Integrated 4 external services with Kafka Broker using Spring Cloud Streams to streamline data flow (routing, preprocessing, and validation) and enhance processing efficiency.· Decomposed a monolithic application into microservices with Kafka and REST API, achieving a 4-fold improvement in average HTTP request performance.· Developed over 200 e2e tests for integration logic, tripling the speed of new feature implementation and boosting overall development efficiency.· Co-developed a state-machine framework with Spring State Machine to manage document lifecycles for 20+ document types, accelerating workflow automation.· Created and maintained documentation to standardize code practices for a team of 6 developers, improving consistency and collaboration.

Personal Development Application based on Microservice Architecture • Integrated the corporate portal's authentication process with an independent authorization system, enabling seamless integration of 2 additional applications for over 600 corporate clients• Developed a notification service for emails and messengers using HTML templates and Kafka messaging, establishing a new communication system• Improved performance of the development plan service, achieving a 6-fold increase in in the speed of the most-used HTTP queries

Warehouse Backend System Based on Microservice Architecture• Developed a return management service from scratch, collaborating closely with the business team for technical consultations, which reduced unsorted products by 5 times• Initiated and launched an inventory excess reporting service using Kafka, reducing overhead on other services and providing real-time overstock alerts.

Full-stack Banking Application Based on a Monolithic Engine• Developed backend logic and REST API for a mobile banking in-app game• Contributed to new features for the web client using Apache Tapestry