Aliaksei V.

Senior Java backend engineer with 8+ years of building Spring Boot microservices, most of them in fintech. What I do well: • Spring Boot microservices for financial transactions, built to stay reliable under high load (99.9% uptime on critical services in my current role) • Event-driven systems with Kafka and RabbitMQ: low-latency service-to-service communication, retries, idempotent processing • PostgreSQL performance: query and index optimization, transaction management, Hibernate/JPA • Payment and third-party API integrations, process orchestration with Camunda • Authentication and security with Spring Security and Keycloak • Delivery and observability: Docker, Kubernetes/OpenShift, Grafana, GitLab CI, Jenkins • Full-stack when the project needs it: Angular/TypeScript, React Selected work: • Fintech microservices (2022 to now): transaction-processing services with Kafka, RabbitMQ, GraphQL and PostgreSQL on Kubernetes/OpenShift and Google Cloud; rate limiting and performance work for a large number of users. • Financial application (3 years): Spring Boot business logic for transaction and application processing, Camunda workflows with state management, payment-gateway integrations, Angular UI. • Utility-meter data platform: Kafka-based data processing and a migration from PostgreSQL to ClickHouse that significantly sped up analytical queries. • On Upwork: public bus dispatching system (legacy Java backend + React, real-time vehicle tracking), Keycloak and Spring Security authentication work, Angular + Spring Boot web applications, CSV to ClickHouse ingestion on Azure. How I work: clear written English, comfortable async. I start by understanding the existing codebase and business rules, cover changes with unit and integration tests (JUnit, Testcontainers), and leave documentation behind. Based in Brussels (CET): full overlap with European hours and US East Coast mornings. Open to long-term contracts and well-scoped fixed-price projects.