11/10/2026 updated
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Software Engineer & Tech Lead | Kotlin/Java, Spring Boot, Kafka, Kubernetes
Bratislava, Slovakia
Only remote
Bachelor of Engineering (Bc.), Technical University of Kosice, 2018-2021About me
Senior backend engineer and team lead from Bratislava. I build Kotlin/Java services where data has to be right: Kafka pipelines, payments, banking integrations. Remote, B2B via my own Slovak company. English for work; Ukrainian, Russian, Slovak.
Java (Programming Language)PostgreSQLRabbitMQSystems IntegrationSpring BootBackendSpring DataKotlinKubernetesApache KafkaFront End Software DevelopmentApi DesignApi GatewayMicroservices
Kotlin & Java Backend Development
Extensive experience building backend services and microservices with Kotlin, Java and Spring Boot, including Spring Security, Spring Data and Hibernate, covering the full path from requirements to production.
Microservices & Distributed Architecture
Deep expertise in microservices architecture, event-driven design, domain-driven design, REST API design, API gateway patterns and RFC 7807, applied in large-scale enterprise and consumer platforms.
Kubernetes & Cloud Infrastructure
Hands-on experience with Kubernetes, Docker, Helm, ArgoCD, GitOps and CI/CD pipelines, including blue-green deployments and on-premise Kubernetes hosting with Nginx and TLS.
Messaging & Streaming
Practical experience with Apache Kafka, RabbitMQ and Apache NiFi for building event-driven and data pipeline solutions in enterprise environments.
Databases
Proficiency with PostgreSQL, Oracle, Redis, Liquibase and Flyway, including query optimization for high-frequency read and write workloads and schema versioning.
Observability & Monitoring
Setup and configuration of observability stacks using OpenTelemetry, Grafana, Tempo, Loki, Prometheus and distributed tracing to ensure reliability and performance.
Security & Authentication
Implementation of authentication and authorization solutions using Keycloak, OAuth2, OIDC, JWT and role-based access control in enterprise and consumer applications.
Frontend Development
Experience with React, React Native, Angular and Next.js, including building mobile apps for iOS and Android, analytics dashboards and server-side rendered frontend features.
Testing & Quality Assurance
Writing integration and unit tests with JUnit and Mockito, conducting code and architecture reviews, and maintaining consistent technical standards across teams.
Experience
Professional experience5 - 10 years
Freelancer since2025
Languages
EnglishGoodRussianFluentSlovakFluentUkrainianNative speaker
Project history
Leading the team working on an enterprise data pipeline platform using Apache NiFi, Kafka, RabbitMQ, PostgreSQL and Spring Boot microservices on Kubernetes. Responsible for much of its architecture, turning business requirements into service boundaries and data flows, maintaining deployments with ArgoCD and GitOps, setting up observability with OpenTelemetry, Grafana, Tempo, Loki and Prometheus, proposing API conventions, and conducting code and architecture reviews.
Designed and built a production marketplace as the sole engineer using Java and Spring Boot backend with PostgreSQL, a Kafka-driven notification service, React Native app on iOS and Android, and a React analytics dashboard. Implemented OIDC and JWT authentication with Keycloak, real-time chat, notifications and live updates. Dockerized services behind Nginx with TLS on Hetzner, responsible for everything from database schema to deployment and operations.
Delivered features end to end in a system of more than 10 microservices at Austria's largest banking group. Designed and modeled RESTful APIs including integrations with external and third-party systems, contributed to API infrastructure design, participated in architecture reviews, and worked on CI/CD pipelines with blue-green deployment for zero-downtime releases.