Java Full-Stack Developer

Java Full-Stack Developer (Freelance) - 13 Months - Brussels, Belgium

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About The Role We are seeking a Senior Java Full-Stack Developer (Freelance) to join our client’s major business transformation program in Brussels. This is a high-impact opportunity to shape and modernize critical business applications, working alongside a dynamic team of 70+ professionals. Your expertise will drive the evolution, refactoring, and greenfield development of essential systems, directly influencing the future of digital services.

Why This Role Matters

This role is pivotal in ensuring the seamless handover, modernization, and creation of business applications that power our client’s core operations. As a builder, your contributions will solve complex integration challenges, enhance system reliability, and accelerate digital transformation. The stakes are high: your work will empower teams, streamline processes, and deliver tangible value to end users across the organization.

Key Responsibilities

Design, develop, and maintain robust Java-based business applications in a full-stack environment

Build and enhance application components and web services (SOAP \& RESTful)

Collaborate closely with technical leads and software architects to shape architecture components and building blocks

Participate in technical working groups, Scrum ceremonies, and user meetings as needed

Support testing, technical documentation, deployment, evaluation, and reporting (JUnit, JIRA)

Contribute to both backend and frontend development, ensuring seamless integration and user experience

Mentor and support junior team members, fostering a collaborative and high-performance culture

Technical Skills

5-7+ years of professional Java development experience (full-stack preferred; strong backend with frontend affinity accepted)

Java and Spring Framework (including Spring Security and Spring Batch)

JPA with Hibernate implementation

SOAP and RESTful Web Services

SOA, microservices, CQRS

Test-driven development: JUnit, Spring, CI, Mockito, Cypress, Selenium

Frontend: HTML, CSS, JavaScript, Angular

Build \& DevOps: Maven, Jenkins, Docker, Openshift

Version control: SVN or GIT

IDE: Eclipse or IntelliJ

Quality \& deployment: Sonar, JBoss, Tomcat

Relational databases: PostgreSQL, SQL Server

O/R mapping and ability to read BPMN, UML

Documentation \& collaboration: Jira, Confluence

Nice to have: Talend, ZK, Oracle, Kafka

Language Proficiency

French or Dutch: Active knowledge (understanding, speaking, writing technical documentation, reading)

English: Active knowledge (written and team communication)

Other Requirements

Familiarity with multi-system integration and complex environments

Experience with Agile/SCRUM methodologies, test-driven development, and continuous integration

Strong problem-solving skills and ability to quickly understand existing codebases

Solution and customer-oriented mindset

Ability to integrate seamlessly into existing teams and supervise junior developers

Hybrid work model: On-site presence in Brussels with remote flexibility (up to 3 days/week)

Freelance contract: Immediate start through 31/12/2026 (13 months, full-time)

Ready to build the future? Upload your CV and join the movement of elite builders at RELYzIT Talent. Be chosen. Be impactful.

RELYzIT Talent — Where builders build the future.

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