11/03/2026 updated
partially available
info: Available evenings and weekends
Senior Java Developer (English-speaking) | Spring Boot, Microservices, Legacy Modernization
Belgrade, USA
Only remote
BSc Electrical Engineering, University of BelgradeAbout me
Java developer from Belgrade with 15+ years in backend and full-stack work. I like taking ownership from first commit to production, communicating clearly and leaving code cleaner than I found it. Working remotely in English, part-time.
Java (Programming Language)Application Programming Interfaces (APIs)Amazon Web ServicesMicrosoft AzureJava Platform Enterprise Edition (J2EE)HibernateSpring FrameworkPostgreSQLMongoDBRedisSvelteJava Application ServerReact.jsSpring BootBackend
Senior Java backend and full-stack engineer with 15+ years of experience taking products from idea to production. Based in Belgrade, Serbia (CET), working remotely in English with clients from Austria, Germany and the US.
Core skills:
• Java 17+, Spring Boot, Micronaut, Jakarta EE (JEE), Hibernate/JPA
• REST API design (OpenAPI), microservices, distributed systems, hexagonal architecture, Dapr
• Databases: PostgreSQL, MySQL, MongoDB, Redis, Apache Solr; schema design and migrations
• Frontend: React, Svelte/SvelteKit, JavaScript, JSP, JSF, Thymeleaf
• Cloud & DevOps: AWS (EC2, S3, CloudFront), Microsoft Azure, Docker, Jenkins (CI/CD), Nginx, WildFly clustering, Tomcat, Linux
• Testing: JUnit, Mockito, Selenium, Playwright, TDD
• AI integration (OpenAI API) and AI-assisted development (Claude Code, Codex)
Legacy Java modernization:
Years of hands-on work with EJB, Servlets, JSP, JSF, JDBC and application servers (WildFly/JBoss, GlassFish, Tomcat). I upgrade old Java versions to Java 17/21, migrate EJB/Servlet/JSF applications to Spring Boot or modern Jakarta EE, replace JSP/JSF UIs with React or Svelte frontends, and containerize applications for AWS or Azure, step by step and with tests first, so the system keeps running while it is modernized.
Recent projects:
• Energy consumption platform for Salzburg AG (2025–present): real-time microservices with Micronaut, Dapr, Redis and PostgreSQL on Azure
• Fintech investment advisory platform (2025): Spring Boot backend with AI-driven features (OpenAI API)
• Beyond Pulse (2024): athlete heart-rate monitoring platform for team sports; Spring Boot, React, AWS
• Bookkeeping platform for Eurodata (2023–2024): end-to-end feature development and legacy refactoring (Java, Spring Boot, Swing)
• HPE Complete Care (2023): enterprise B2B platform on Java, Spring and JSF
• OOYYO (2010–2023): designed and ran a large-scale vehicle classifieds search engine (architecture, crawlers, data pipelines, ad serving, WildFly cluster)
Availability: part-time (about 20 hours per week), remote only, English-speaking projects. B2B contracts via my registered company in Serbia, invoiced in EUR.
Experience
Professional experience10+ years
Freelancer since2018
Languages
EnglishFluentSerbianNative speaker
Project history
Java and full-stack development on client projects:
• Salzburg AG energy consumption platform (Sep 2025 – present): Micronaut microservices for real-time consumption tracking and analytics, REST APIs with OpenAPI, Dapr, hexagonal architecture, Redis caching, PostgreSQL, Microsoft Azure
• Fintech investment advisory platform (Jan 2025 – Aug 2025): Spring Boot backend services, AI-driven features with the OpenAI API, database schema and versioned migrations
• Beyond Pulse athlete heart-rate monitoring platform (Jun 2024 – Dec 2024): full-stack role; Spring Boot services processing sensor data into athlete and team metrics, React web app for coaches, AWS (EC2, S3, CloudFront)
• Eurodata bookkeeping platform (Aug 2023 – Jun 2024): end-to-end feature development, REST APIs and validation logic, legacy code refactoring (Java, Spring Boot, Swing), code reviews with QA
Worked for Hewlett Packard Enterprise (HPE) on the Complete Care enterprise B2B platform:
• Developed and maintained backend services and the JSF-based web UI
• Delivered new features and resolved production issues
Tech: Java, Spring, JSF, Tomcat
Designed, built and ran OOYYO, a large-scale international vehicle classifieds search engine:
• Owned the architecture end to end (backend, frontend, database)
• Built and maintained the web crawler infrastructure and data ingestion pipelines
• Implemented ad serving and lead generation systems
• Administered production infrastructure: WildFly cluster, Nginx, Linux servers
• Migrated legacy projects from Java 6 to Java 8 with Maven
Tech: Java, JEE, WildFly, MySQL, MongoDB, JSP, jQuery, Selenium, Nginx