Work AS One, aka WASO, is launching its products. We need an experienced Java developer whose technical rigor ensures scalable execution. This is a high-impact, long-term engagement within a small, empowered team built on high trust and shared success. REQUIEREMENTS : Strong experience (min. 3 years) in Java development. You master Java 21+ and designing resilient architectures. Mastery of the Spring Framework (Spring Boot) and RESTful APIs for healthy, performant code delivery. Experience with Spring Security, Spring Data/JPA, Spring Batch, and ideally Spring AI. Apply DDD principles for horizontal scaling and contribute to our DevOps/Cloud environment (Docker, Kubernetes, GitHub Actions, OVH/Azure). Ensure rigorous quality and observability standards (unit/E2E testing, Prometheus/Grafana, Loki) across the application landscape. Expertise in Integration and Data Flow: designing secure layers (Event-driven, OAuth2/JWT) and working with real-time protocols (MQTT, WebSocket). Experience with Mobile and Hardware integrations is a strong plus. Familiarity with our stack (MariaDB/PostgreSQL, Keycloak, Azure Storage, React/TypeScript/Native). Future Focus (AI): We require strong knowledge OR a genuine, demonstrable interest in Artificial Intelligence concepts. Familiarity with specific concepts like RAG/embeddings is a bonus. Ability to ensure consistent execution and meet demanding launch timelines (Velocity). WE'RE LOOKING FOR: Strong experience (min. 3 years) in production-focused Java development. Your technical rigor ensures scalable execution. You are autonomous and actively contribute to collaborative success and knowledge sharing. Ability to ensure consistent execution and meet demanding launch timelines (Velocity). You take full ownership and initiative (Strong "entrepreneurial" mindset). High flexibility to adapt to a fast-paced environment and embrace ambiguity. Your work has a real impact and directly shapes the product's features. Fluent in both French and English (required). Dutch is a plus. Excellent verbal and written communication skills and ability to foster strong team spirit. We value co-creation and team moments. THE WASO VIBE: We welcome employees and freelancers, we want long-term partners. Compensation is fair, and based on your expertise and the value you bring (no pay gaps among peers). You deliver results, we deliver value. No corporate buzzwords. You'll join a fast growing company that will offer a career path with a real impact. You will directly shape our product's features and play a key role in the success of our commercial launch. Your work matters immediately. We value flexibility, but we love being together. We typically work 3 days a week from the office (Belgium-based hybrid) because co-creation and team moments are central to the WASO DNA. Culture: we are a small team that works together and runs on trust. Our offices are welcoming, and guess whaaaat : we're dog-friendly. THE PROCESS : Application & review Vibes & HR check Technical deep dive Final fit & offer READY TO WORK AS ONE ? Shoot your CV to : (more info about WASO : )