Freelance Senior Java Developer

adesso Belgium, who are we? We are an IT (start-up) provider working under the adesso umbrella with proven track record in different industries. The new Belgian entity of adesso is part of the expansion and growth strategy of the adesso group. With more than 10.000 employees spread over 60 locations we are entering an exciting period with our presence in Brussels, the capital of Europe.

We are looking for experienced freelance Java developers to join our talent pool for upcoming projects with our customers in Belgium.

Your role

In this consultant role, you will combine strategy with execution. You are both a visionary and a doer: from architecture and code reviews to implementation and deployment.

• You translate requirements and architecture into technical designs and working software.

• You are responsible for designing, building, testing, and maintaining full-stack software solutions.

• You implement automated tests as a standard part of every development effort.

• You build robust backend components in Java and Spring Boot, and develop corresponding front-end components in Angular, react or vue.

• You introduce new ideas and best practices and use state-of-the-art technology

• You set up REST APIs according to OpenAPI specifications and ensure stable integration with other systems.

• You work with modern CI/CD pipelines (Jenkins, Docker, Kubernetes/OpenShift) and safeguard code quality through test automation.

• You work independently alongside functional analysts who provide the requirements, alongside developers, architects and designers within an Agile scrum team.

• You continuously align your work with the team and communicate progress and technical choices in a transparent, structured way.

• You present your solutions to customers and stakeholders, process feedback, and defend well-founded technical choices.

• You don't code alone: AI is your daily pair-programming partner, and you know how to wield tools like GitHub Copilot to write cleaner code faster, catch bugs before they hatch, and spend your brainpower on the architecture decisions that actually need a human.

Required Skills & Knowledge:

Java (10+ years) / Kotling - Spring Boot - JPA/Hibernate - REST - OpenAPI - Git - Jenkins - Maven - Docker - Kubernetes/OpenShift - Postgres - Message Broker (e.g. ActiveMQ) - Angular, among others

Your profile

• You hold a bachelor's or master's degree in computer science, engineering, or equivalent through experience.

• You have at least 5 years of professional experience as a Java developer.

• You have a strong passion for building high-quality digital solutions and the ability to convince both customers and colleagues.

• You are flexible, work in a structured way, and can quickly adapt and integrate within an Agile team.

• You have knowledge of modern software architectures (microservices, event-driven, cloud-native).

• You have strong, demonstrable experience with Spring Boot, JPA/Hibernate, Jenkins, Maven, Docker, Kubernetes/OpenShift, Postgres, and message brokers.

• If you've ever tamed a stream of Kafka topics without losing a single message (or your sanity), we want to hear about it — Kafka experience is a big plus.

• Experience with a complex project, Domain Driven Design/Clean Code/TDD, BPMN & CMMN, OAuth2, or GitHub Copilot is a strong asset

• Bonus points if Apache Camel feels like second nature to you — routing messages between systems without breaking a sweat is exactly the kind of integration wizardry we're after.

• Proficiency with CI/CD, version control (Git), test automation, and monitoring too

• You can communicate fluently in French or Dutch (active proficiency), and in English.

Why join adesso Belgium?

• Work in an international group with strong local expertise in Belgium.

• Collaborate with cross-functional teams within the international data & AI adesso community.

• Flexible freelance setup with the support of a growing adesso Belgium community.