Java Developer vacatures in Brussel

itsme® has fundamentally changed how people lead their digital lives in Belgium, but we are not stopping there! Do you want to be a driving force to help expand on this success story as part of a talented team that is making a positive impact on society? Then keep on reading, you’ll probably like what you’ll see.

We are itsme®, one of Europe’s fastest-growing scale-ups, with 115 team members and growing. Our mission: to provide a state-of-the-art digital identity solution for all people, enabling them to interact securely in the digital space. Now, only nine years after being founded, close to 8 million citizens use the itsme® app to identify themselves and sign documents online. Starting in Belgium, we successfully launched the itsme app in 32 European countries, with the ambition of becoming an internationally leading player.

We are looking for a dedicated Java Backend Developer to help us maintain, optimize, and evolve our core backend system. If you thrive on reverse engineering, digging into legacy codebases, and turning complexity into clarity, this could be your next challenge.

This role is ideal for someone who loves to get under the hood of complex systems and improve stability, maintainability, and performance.

What your job looks like

As a Java Backend Developer, your mission is to take full ownership of our existing backend system. This is a brownfield environment: no greenfield development from scratch, but rather deep technical work on a mature codebase that powers the heart of itsme®.

Your daily work will involve:

• Understanding and maintaining our monolithic Java application running in production.
• Investigating and resolving bugs, optimizing performance, and ensuring reliability.
• Reverse engineering the current system to identify modular components and support future architecture plans.
• Supporting CI/CD processes and helping evolve our deployment pipelines.
• Collaborating with our architecture team to gradually refactor and modularize the backend into more manageable components.
• Ensuring that the “invisible engine” behind our app runs seamlessly for millions of users.

• Minimum of 4 years of experience in backend development, with a focus on Java & Spring Boot;
• Strong experience with backend architecture and legacy systems, especially those needing reverse engineering, refactoring, and optimisation;
• Demonstrated experience in optimising and cleaning up a backend, particularly for brownfield project;
• Experience with CI/CD processes (e.g., Github workflows, automated builds, pipelines);
• Exposure to working with Kubernetes for deployment and containerisation;
• Solid experience in SQL, database management, and related backend technologies;
• Experience in highly regulated or security-sensitive environments is a plus, given the nature of the project.
• Willingness to grow beyond the current stack and contribute to a changing technical landscape
• Strong motivation to work in evolving environments where systems are actively being phased out or re-architected
• Curiosity and willingness to learn new technologies and paradigms (e.g. Go, distributed systems)

What we offer

• Being welcomed by an informal, enthusiastic, and ambitious team that is revolutionising how we safely manage our digital identity, in Belgium & beyond.
• Offices within walking distance from Brussels Central Station, with the possibility to work remotely 3 days a week.
• A contract of indefinite duration, with an attractive compensation package.
• An environment where we care a lot about our core values:
  • Integrity: being fair, honest & transparent so that we can be trusted.
  • Inclusiveness: being an open environment in which all team members' opinions are taken into account.
  • Innovation: building future-proof solutions by finding new ideas and methods to solve problems.