WHO WE ARE Edda International, a dynamic and rapidly growing European group of companies with an estimated 2024 turnover of 20+ MEUR, 220+ employees and 15+ years of experience. Operating out of Luxembourg and Brussels, Edda International manages large International Institutions Framework Contracts delivering Information Technology services throughout geographical Europe. WHAT WE ARE LOOKING FOR Senior Java Backend Developer (English + French or Dutch) We are currently looking for multiple profiles - Advanced (6) and Expert (1) - with proven Java/Spring Boot and integration expertise to join our client's projects in Brussels in the energy & utilities domain.The mission involves delivering API-enabled Domain Services and integrations, including REST/SOAP services, GraphQL, and event-driven patterns with Kafka within agile squads/chapters. In this role, you will: Analyse, develop and maintain functionalities across Java-based Domain Services, with a focus on REST/SOAP APIs, GraphQL, and asynchronous/event-driven integration patterns (e.G., message queues, Kafka). Work within agile squads/chapters to support business priorities and integration objectives. Expert track: guide other developers, perform quality controls, produce detailed designs for Java-based Domain Services, and advise on general integration topics; may also contribute to JavaScript applications and CMS components where required. YOUR TASKS Deliver and evolve Java/Spring Boot services for integration use cases. Design and implement REST APIs and SOAP services; contribute to GraphQL integrations. Implement asynchronous/event-driven patterns with Apache Kafka and message queues. Collaborate within agile teams (squads/chapters) to support business priorities. Expert track: perform code/design reviews, guide/coach peers, produce detailed designs for Domain Services, and advise on integration best practices; contribute to JavaScript/TypeScript apps and CMS components when applicable. YOUR SKILLS AND EXPERIENCE Specific expertise (mandatory):Advanced (min. 5 years): Java, Spring Boot GraphQL Apache Kafka REST API and SOAP service development Asynchronous integration patterns (event-driven architecture, message queues) Expert (8+ years, incl. leadership & setup): Java 11/17 (5y), Spring/Spring Boot (5y), Spring MVC (2y) REST API design (5y), JAX-WS/JAX-RS (3y), XML processing (2y), SOA principles (3y) JavaScript/TypeScript (5y); 2 (1y);responsive HTML/CSS (1y) for related application/CMS components Hands-on cloud deployments: Microsoft Azure/Azure DevOps, Docker, Kubernetes (5y); able to guide others and perform quality controls; produce detailed designs for Java-based Domain Services and advise on integration topics Additional strong knowledge in: AWS (e.G., EKS, SQS, S3); PostgreSQL; CI/CD pipelines, monitoring and logging in cloud-native environments; Kubernetes LANGUAGES: English - fluent (mandatory) both spoken and written B2 Dutch or French - as a secondary language B1 ADDITIONAL INFORMATION Contract type: Freelance Start date: 17-24/11/2025 Location: Brussels, Belgium Work mode: 2 days per week on-site in Brussels, Belgium Relocation: Relocation is required for candidates who do not yet reside in Belgium or its border region. Levels of seniority Advanced: min. 5 years of experience Expert: 8+ years, including leadership and setup experience Eligibility: Open to EU citizens and non-EU citizens already residing in the EU with a valid work permit. APPLICATION PROCESS If this opportunity excites you, please send your CV to Edda International. Applications will be processed confidentially. Only selected candidates will be contacted for the next steps. DIVERSITY AND INCLUSION At Edda International, we are committed to supporting a Diverse and Inclusive Community.