One of our leading banking partners is looking for a freelance Backend Java Engineer to take technical ownership of a legacy core lending system and support its evolution. This isn’t greenfield : it’s a real challenge for a real engineer who thrives in complex codebases and can strike a balance between modernisation and stability.
Logistics :
- Position : Freelance Backend Java Developer (Legacy Systems Specialist)
- Duration : 24-Month Contract
- Location : Brussels (Hybrid - 2 days / week onsite)
- Languages : English (French or Dutch is a bonus, not a must)
- Start Date : 30 June 2025
- Day Rate : €(Negotiable & Competitive)
Core Responsibilities :
Maintain and incrementally modernise a core lending system built on a legacy Java stackDesign, refactor, and evolve Java components using Spring (non-Boot)Interface with XML-based integrations and SOAP web servicesHandle message-driven workflows using KafkaCollaborate with cross-functional teams to maintain quality, stability, and incremental improvementsWork closely with technical leads on technical debt reduction and architecture improvementsEssential Skills :
6+ years of Java development experience, especially in large-scale enterprise systemsStrong command of core Spring (non-Boot), object-oriented design, and clean code principlesHands-on experience with SOAP services and XML-based communicationFamiliarity with Kafka and Kubernetes in production environmentsAbility to work in a CI / CD-driven environment using Git, GitLab, Jenkins, SonarQubeSolid understanding of legacy systems : how to respect them, work with them, and gradually improve themDesirable Skills :
Experience with Domain-Driven Design or hexagonal architectureKnowledge of Oracle databases and service bus architecturesFamiliarity with Fortify, Nexus, and other security / dependency toolsPast exposure to modernising monolithic applications without destabilising themWhat You Bring :
Technical patience - you understand that working on legacy isn’t glamorous, but it’s criticalCuriosity - you ask “why” before you rip and replaceTeam spirit - this is a collaborative squad that values inputProblem-solving - deep-diving into decades-old code doesn’t scare youWhy This Role Matters :
This isn’t a typical Java contract. You’ll be touching the core of a system that handles critical banking operations - used by thousands, shaped over years, and in need of careful, expert handling.
Interested? Let’s talk. This is a key hire for one of Belgium’s most trusted financial players - and a chance to do meaningful technical work at scale.
