11/04/2026 updated
AB
100 % available
Senior Java Backend Engineer | Spring Boot | Apache Kafka | Camunda BPM | PostgreSQL
Bar, Montenegro
Only remote
Specialist degree (Master's equivalent), Financial University under the Government of the RFAbout me
Senior Java backend engineer, 7 years in product teams. High-load event-driven systems: Kafka, Camunda BPM, PostgreSQL, Spring Boot. Based in Montenegro (CET), fully remote, B2B contracts via own legal entity.
PostgreSQLRabbitMQPrometheusSpring CloudSpring MVCBackendSpring DataBackend ProgrammingKubernetesApache KafkaApi DesignMicroservices
Java & Kotlin Backend Development
Extensive expertise in Java 8-21 (Core, Concurrency, Stream API, JVM/GC) and Kotlin, with hands-on experience building high-load, event-driven microservices using Spring Boot 3, Spring MVC, Spring Data JPA, Spring Security, and Spring Cloud.
Apache Kafka & Messaging
Deep knowledge of Apache Kafka in production environments, including idempotent producer, acks=all, retries, DLQ, ack/nack patterns, Claim-Check pattern, and event-driven architecture. Experience with RabbitMQ and Spring for Apache Kafka.
PostgreSQL & Database Performance
5+ years of PostgreSQL experience covering query and index optimisation, schema normalisation, Liquibase migrations, performance refactoring, and database maintenance including VACUUM FULL and history TTL management. Additional experience with Oracle, Redis, and MongoDB.
Camunda BPM & Business Process Orchestration
Practical experience implementing full campaign lifecycles as multi-step BPMN 2.0 processes on Camunda 7, owning and developing core orchestration services across 10+ microservices and 20+ Kafka topics.
Microservices Architecture & Design Patterns
Solid background in designing and building microservices with event-driven design, Claim-Check, orchestration, REST, and OpenAPI 3. Application of SOLID principles and design patterns such as Strategy and Template Method.
Cloud & DevOps
Hands-on experience with Docker, Kubernetes, Helm, GitLab CI, private corporate cloud, and GCP (Cloud Storage). Observability tooling includes Micrometer, Prometheus, Grafana, and Jaeger.
Testing & Quality Assurance
Proficiency in writing and maintaining tests using JUnit 5, Mockito, and Testcontainers. Active participation in code review within distributed Scrum teams.
Security & API Design
Experience with Spring Security, Keycloak, JWT, and RBAC for securing REST APIs. API documentation and contract design using OpenAPI 3 and Swagger.
AI-Assisted Development
Daily use of AI-assisted development tools including GitHub Copilot and Claude Code to enhance productivity and code quality.
Extensive expertise in Java 8-21 (Core, Concurrency, Stream API, JVM/GC) and Kotlin, with hands-on experience building high-load, event-driven microservices using Spring Boot 3, Spring MVC, Spring Data JPA, Spring Security, and Spring Cloud.
Apache Kafka & Messaging
Deep knowledge of Apache Kafka in production environments, including idempotent producer, acks=all, retries, DLQ, ack/nack patterns, Claim-Check pattern, and event-driven architecture. Experience with RabbitMQ and Spring for Apache Kafka.
PostgreSQL & Database Performance
5+ years of PostgreSQL experience covering query and index optimisation, schema normalisation, Liquibase migrations, performance refactoring, and database maintenance including VACUUM FULL and history TTL management. Additional experience with Oracle, Redis, and MongoDB.
Camunda BPM & Business Process Orchestration
Practical experience implementing full campaign lifecycles as multi-step BPMN 2.0 processes on Camunda 7, owning and developing core orchestration services across 10+ microservices and 20+ Kafka topics.
Microservices Architecture & Design Patterns
Solid background in designing and building microservices with event-driven design, Claim-Check, orchestration, REST, and OpenAPI 3. Application of SOLID principles and design patterns such as Strategy and Template Method.
Cloud & DevOps
Hands-on experience with Docker, Kubernetes, Helm, GitLab CI, private corporate cloud, and GCP (Cloud Storage). Observability tooling includes Micrometer, Prometheus, Grafana, and Jaeger.
Testing & Quality Assurance
Proficiency in writing and maintaining tests using JUnit 5, Mockito, and Testcontainers. Active participation in code review within distributed Scrum teams.
Security & API Design
Experience with Spring Security, Keycloak, JWT, and RBAC for securing REST APIs. API documentation and contract design using OpenAPI 3 and Swagger.
AI-Assisted Development
Daily use of AI-assisted development tools including GitHub Copilot and Claude Code to enhance productivity and code quality.
Experience
Professional experience5 - 10 years
Freelancer since2026
Languages
EnglishGoodRussianNative speaker
Project history
Building a high-load, event-driven CVM/personalised marketing platform for a top-3 federal grocery retailer. Responsibilities include database growth incident resolution (800+ GB to ~200-250 GB), cross-service Kafka consistency improvements, loyalty status update fixes, designing a new audience microservice using Claim-Check pattern, owning the core orchestration service with a 14-step BPMN 2.0 process on Camunda 7, and implementing observability with Micrometer, Prometheus, Grafana, and Jaeger. Stack: Java 17/21, Kotlin, Spring Boot 3, Spring Security, Spring Data JPA, Spring Cloud, Apache Kafka, PostgreSQL, Redis, MongoDB, Camunda 7, Hibernate, Liquibase, REST, OpenAPI 3, Keycloak, Docker, Kubernetes, Helm, GitLab CI, Micrometer, Prometheus, Grafana, Jaeger, JUnit 5, Testcontainers, Gradle, Maven.
Developed high-load billing and order-processing microservices for a Telecom BSS platform covering order management, billing, rating, and subscriber management. Built RESTful APIs with Spring MVC, improved PostgreSQL performance through schema normalisation and indexing strategies, applied Java Concurrency and Stream API for parallel processing, and used Docker, Kubernetes, Prometheus, and Grafana for deployment and monitoring. Stack: Java 11, Spring Boot, Spring MVC, Spring Data JPA, Hibernate, PostgreSQL, Liquibase, REST, OpenAPI, Docker, Kubernetes, Prometheus, Grafana, JUnit 5.
Developed backend business logic for a CRM platform for a regional pharmacy chain covering inventory, assortment, automatic pricing, and reporting. Implemented service, repository, and DTO layers on Java 8, Spring Boot, Spring MVC, and Spring Security. Performed PostgreSQL schema design, query optimisation, and performance refactoring using Hibernate/Spring Data JPA. Handled REST API integration and Maven builds.