Oleh Doinin

Java Full Stack Developer with 3+ years of experience building and scaling backend services, RESTful APIs, and microservices in Spring Boot / Spring Cloud environments. Strong background in refactoring legacy monolithic systems into independent microservices, optimizing SQL queries and multithreaded processing, and integrating AWS cloud infrastructure (S3, Lambda, SQS) for scalable data pipelines. Comfortable across the stack, from React/JavaScript frontend work to database design, CI/CD, and test automation.

Actively using AI coding tools and agent-based workflows (MCP, AI agents) to speed up development and code review.

Full Stack Java Developer at GlobalLogic (2025-01 – Present)

• Developed and maintained backend microservices with Java 8, Spring Boot, Spring MVC, and Spring Security, and optimized a React.js front-end for performance and maintainability.
• Owned the full lifecycle of a microservice from initial design through to production release and complete technical documentation.
• Refactored legacy monolithic modules into independent, scalable microservices, reducing coupling and easing future maintenance.
• Integrated AWS services (S3, Lambda, SQS, EC2, VPC, ElastiCache) to support data storage, asynchronous processing, and application scalability.
• Implemented asynchronous, event-driven communication between microservices using RabbitMQ, and applied multithreading/concurrency patterns (Project Reactor) to improve throughput.
• Optimized SQL queries and managed database transactions across PostgreSQL, MySQL, and Redis to improve response times.
• Built an internal admin panel for managers using HTML, JavaScript, CSS, and React.js.
• Wrote comprehensive unit and integration tests (JUnit, Mockito, JMeter, Selenium) as part of a CI/CD pipeline (Jenkins, Docker, Tomcat).
• Integrated the internal platform with external systems, including Tabletki.ua, and maintained direct communication with stakeholders to gather requirements and deliver regular updates.

Junior Java Developer at Конекс (2021-01 – 2025-01)

• Developed and supported backend features using Java 8, JDBC, Hibernate/JPA, and Spring Boot under the guidance of senior engineers.
• Worked with relational databases (PostgreSQL, MySQL), writing and optimizing SQL queries for application features.
• Wrote unit tests (JUnit, Mockito) to improve code coverage and reliability of new features.
• Collaborated using Git/GitHub and CodeCommit in a Scrum team environment, participating in code reviews and sprint ceremonies.
• Gained hands-on exposure to legacy monolithic architecture, laying the groundwork for later microservice refactoring work.

Computerized Information and Measurement Technologies – Vinnytsia National Technical University (2021-01 – 2025-01)