NEOFACTO - Java Software Engineer à Paris 06, France

We are loonking for a Java Software Engineer. You will take ownership of the full software development lifecycle, from critical, high-throughput backend services to modern web and mobile user interfaces. Missions Architect and implement scalable, maintainable, and decoupled MicroServices architectures Define robust, well-documented REST APIs and JSON integration contracts to ensure seamless integration with client applications (particularly React front-ends) Design event-driven, asynchronous data pipelines using Apache Kafka Make high-impact decisions regarding system resilience, performance optimization, and architectural modularity Build enterprise-grade backend services leveraging modern Java language features (Java 17/21+) and Spring Boot 3.x Deconstruct and reverse-engineer complex legacy codebases: MAP out dependency graphs, formulate phased migration strategies, and align technical refactoring with core business priorities Design relational database schemas and optimize data access layers (JPA/SQL) Orchestrate long-running, distributed business workflows using engines like Temporal Drive software quality and test coverage through robust unit, integration, and mocking suites (JUnit/TestNG, Mockito) Implement modern observability patterns (Spring Boot Actuator, distributed tracing, metrics) Work in an Agile/Scrum environment, participating actively in sprint ceremonies, architectural spikes, and code reviews Collaborate with frontend engineers to streamline API integration and UI/UX synchronization Profile Mandatory experience & qualifications: 7+ years of professional software engineering experience with enterprise Java and modern Spring Boot applications (Java 17 required; Java 21+ strongly preferred) Solid experience designing and coding complex applications, with an emphasis on MicroServices, modular backend design, clean APIs, and frontend-backend integration patterns (React + Spring Boot) Deep expertise in REST services, JSON-based integration patterns, and event-driven architectures with Apache Kafka Solid, hands-on experience working with relational databases (data modeling, query optimization) Strong familiarity with Agile/Scrum delivery and fluent professional English (written and spoken) Preferred experience & differentiators: Proven ability to analyze complex legacy codebases, identify dependency networks, design pragmatic migration roadmaps, and justify architectural decisions to business stakeholders Experience with Spring Framework 6.x and Spring Boot 3.x (Actuator, Observability, and optional Graalvm native compilation) Practical experience with JPA / Hibernate Strong proficiency with JUnit/TestNG and mocking frameworks like Mockito Hands-on experience with the Temporal workflow orchestration engine Basic understanding and working knowledge of React Our offer Working in a Great Place to Work based in Luxembourg Attractive salary and pretty cool benefits (meal vouchers, mobile subscription...) Develop your skills and ideas over a coffee, a beer or a pizza during our Neo'vations Evolve within a strong company culture, you'll join us for the opportunity and you'll stay because we're super cool (well according to 98% of our employees NEOFACTO Annual Survey 2024) Between afterworks, innovative workshops and ski weekends, there's never a dull moment when you're part of the Neo'Squad Recruitment process The pre-qualification interview with our Recruitment Manager Technical tests Receipt of our salary proposal / exclusivity agreement Proposal of your application to the client Interview at the client's premises, which can be conducted either by video or in person Created in 2000, NEOFACTO is a major player that supports companies in their digitalization. Navigating between the creativity of startups and the experience of large groups, NEOFACTO has the ability to position itself and adapt to all projects. Guided by our passion for innovation, we support our customers with the goal of pioneering the new technologies and commercial models of tomorrow. Are we a dynamic and innovative team? Yes! And above all, a team that is united and driven by a very strong corporate culture. We share and cultivate common values to build together the NEOFACTO of tomorrow! You will join us for an opportunity and stay for the people around you.