Tech stack; Java 14\17, Spring Boot, PostgreSQL, Kafka, GCP. - Developed and maintained scalable backend systems for gaming platforms using Java, Spring Boot, and associated technologies. - Collaborated in cross-functional teams to design and implement microservices in a new feature for push notifications through FCM topics. - Conducted code reviews and collaborated in Agile/Scrum environments to ensure high-quality output.

Tech stack; Java 17\21, Spring Boot, PostgreSQL, Clickhouse, Grafana, ELK, Kafka, Kubernetes. - Designed and implemented a configurable microservice architecture to handle “missing match results” — enabling automatic detection of incomplete events in Kafka and Slack alerting for the support team. Reduced bet settlement delays by ~80% and improved operational visibility. - Refactored the event ingestion pipeline: replaced a single Kafka consumer (handling 11 topics) with 11 dedicated consumers, each with its own consumer and listener settings. Improved message throughput by ~3.5× and ensured fault isolation for each topic and non-blocking create operations to Clickhouse. - Developed and maintained backend services for a high-load sports betting platform, integrating with external providers and scrapers while ensuring scalability and reliability under 100K+ daily transactions. - Led zero-downtime migration from Java 17 to Java 21 across microservices: resolved deprecated dependencies and implementations issues, enabled Virtual Threads in selected services with IO operations. Achieved faster cold starts (~25–35%), cut thread footprint for I/O-heavy consumers.

Tech stack: Java 17, Guice, Hadoop, Kafka, Dropwizard. Hubspot CRM. - Built configurable microservices around HubSpot CRM client’s card (meetings, notes, scheduled calls, document exchange, contract & amounts), ensuring clean APIs and access control. - Ensured transactional outbox + exactly-once semantics across integrations; zero missed events in production. - Designed and implemented acceptance tests for each feature within my microservice groups, improving reliability and overall system quality.

Tech stack: Java 8, spring Boot, MsSQL, ELK, Openshift, Keycloak, Kafka - Developed high-load microservices for telecom domain, including chatbots and voicebots for clinic appointment scheduling and credit card delivery. - Designed and implemented multi-tenancy architecture, including a custom Spring Cloud Config analog for dynamically selecting tenant-specific data sources and configuring Spring beans per tenant. - Ensured robust CI/CD pipelines, containerized deployments, and monitoring/logging using Docker, Kubernetes, OpenShift, and ELK stack. - Applied CQRS pattern for each tenant, separating read and write databases, and implemented inter-service communication via Apache Kafka, ensuring scalability and reliability.

- Manual functional, regression, unit and integration testing - API testing - DB testing - Test plans, test cases, checklists creation - QA documentation and reports creation Tech.: PostgreSQL, Postman, Docker, Jenkins, Git, Testrail, Jiraю

Web application and native mobile app (iOS, Android) - Manual functional, GUI, regression, unit and integration testing. - Mobile testing (UI\UX and functionality) - API testing. - Investigation and creating a list of mobile devices, OS for web-app. - Creating QA documentation, test cases, checklist, test plan and reports.