Senior Fullstack Java Developer (M/F)

On behalf of one of Luxembourg's leading insurance groups, GS Advisory is looking for several Fullstack Java Developers to join a multidisciplinary Agile team on a long-term mission. You will work on a business-critical application portfolio within the local contracts domain, in an environment where code quality, autonomy and knowledge sharing genuinely matter.

This is a role for developers who enjoy taking ownership of a mature system: understanding its history, mastering its business rules, and modernising it step by step rather than rewriting it from scratch.

The mission

- Design, develop, test, deploy and monitor applications, primarily in Java 8.

- Maintain and evolve REST APIs written in Scala and existing frontend interfaces, and contribute to the progressive modernisation of a legacy application portfolio.

- Take an active part in Agile ceremonies and practices (Kanban and Scrum) within a multidisciplinary team.

- Write and maintain automated tests (Playwright), and use AI-assisted development tools daily to improve quality, maintainability and productivity.

- Build deep functional and technical expertise on a strategic business domain, and support your colleagues through pair programming, code reviews and knowledge sharing.

Your profile

- 5+ years of hands-on experience as a Fullstack Java developer, ideally in an Agile environment.

- Excellent command of object-oriented programming in Java 8 and above, including the full software development lifecycle.

- Solid frontend fundamentals: HTML, CSS and JavaScript, with the ability to consume and integrate REST APIs.

- Practical experience with relational databases (DB2 is a strong plus) and with designing and building REST APIs.

- Appreciated: functional programming (Scala), COBOL, Kafka, MongoDB, asynchronous Bash processing, JSON:API, Kubernetes, Datadog or Sentry, Git.

What we offer

- A long-term mission running until the end of 2026, with a strong likelihood of extension into 2027.

- A technically demanding environment with real ownership, plus the opportunity to grow into Scala and potentially Angular as priorities evolve.

- Based in Luxembourg, on site a minimum of 3 days per week, with up to 2 days of remote work per week, subject to the tax regulations of your country of residence.

- Full-time or part-time applications are both considered: simply tell us your availability.

- Company canteen, time-tracking system with recoverable hours, and a location well served by public transport (free across Luxembourg).