Senior Java Full Stack Developer

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

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At RELYzIT Talent, we don’t recruit — we build. We unite the top 2% of builders — engineers, architects, creators — into a movement across Europe and the GCC. Vetted through our VECTOR7™ Signal Stack, you’re not just hired, you’re chosen. This is more than work. This is where builders build the future.

We’re seeking a Senior Java Full Stack Developer (Freelance) for a 13-month mission-critical project with our client in Aalst, Belgium. This is your opportunity to drive environmental impact at scale, shaping the digital backbone of Europe’s most important environmental reporting systems.

Why This Role Matters

The Industrial Emissions Directive (IED) and the Industrial Emissions Portal Regulation (IEPR) are reshaping how Europe and Flanders protect air and water quality. Our client is at the forefront, rebuilding the entire digital ecosystem for environmental data collection, validation, and reporting. As a Senior Java Full Stack Developer, you’ll be instrumental in modernizing these systems, ensuring regulatory compliance, and enabling transparent, data-driven environmental stewardship for generations to come.

What You’ll Be Doing

• Collaborating with architects to review and prepare technical analyses and designs


• Developing robust backend services using Spring Boot, with a focus on security and scalability


• Building modern Angular single page applications for seamless user experiences


• Defining and implementing interfaces across architectural layers


• Potentially developing NodeJS backend-for-frontend services


• Driving test-driven development with comprehensive unit tests (JUnit)


• Ensuring non-functional requirements (performance, security, maintainability) are met


• Conducting peer code reviews following gitflow principles (Bitbucket)


• Leading and coaching development teams within an Agile environment


• Delivering high-quality code, testing, and debugging with precision


• Contributing to the complete overhaul of backend systems and data warehouses supporting environmental reporting

What We’re Looking For

• Proven expertise in developing Java-based applications (Senior level)


• Hands-on experience with Angular (versions 2–17)


• Strong background in Docker and Kubernetes


• Advanced skills in JUnit and test-driven development


• Solid knowledge of public cloud infrastructure


• Formal education with certification or equivalent experience in Java/J2EE and related environments


• Demonstrated leadership in development teams and coaching other developers


• Fluency in Dutch at CEFR level C2 (mandatory)


• Experience with Bitbucket (git), Domain Driven Design (DDD), HTML5, CSS, Jenkins, Linked Open Data (LOD), Maven, REST, Spring, and Terraform


• Expertise in Agile development methodologies, with the ability to take a leading role


• Proficiency in JavaScript and TypeScript


• Certified Scrum Master (preferred)


• Experience with NodeJS and npm (nice to have)


• Knowledge of water quality monitoring networks and measurement software (nice to have)


• Experience with PostgreSQL (version 11+), and familiarity with government or VMM technical standards (nice to have)

Language Proficiency

• Dutch language proficiency at European CEFR level C2 is required

Other Requirements

• Freelance position for a 13-month project based in Aalst, Belgium


• Work is delivered within an Agile environment, with partial on-site presence as mutually agreed


• Our client provides necessary licenses, software, and network access (excluding Office license)


• Office 365 software can be provided without a license; candidates may use their own business license or opt for LibreOffice


• Interviews will be held in the second half of August