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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior Fullstack Java Developer - **Company:** Keystone Solutions - **Location:** Sint-Joost-ten-Node, Belgium (Remote available) - **Experience:** Expert - **Contract:** Temporary contract - **Skills:** Java (Programming Language), Software Applications, Architectural Patterns, Confluence, JIRA, Cloud Computing, Computer Programming, Relational Databases, IBM Websphere Application Server, IntelliJ IDEA, Spring Framework, JavaServer Faces, Junit, Apache Maven, MySQL, OpenShift, Scrum Methodology, Cloud Services, Swagger, Simple Object Access Protocol (SOAP), SonarQube, SQL Databases, Openapi, ReactJS, System Availability, Spring-boot, Technical Debt, Git, Containerization, AngularJS, Information Technology, Npm(Software), Graphql, Api Design, Docker, Microservices - **Published:** September 16, 2026 - **Apply:** https://www.adzuna.be/details/5885780441 ## About the Role * Proven experience (5-7+ years) in complex IT programming. * Expertise in modern Java (Spring, microservices, API-driven, event-driven). * Skills in containerization and orchestrators (OpenShift). * Advanced knowledge of relational databases (MySQL) and data modeling. * Knowledge of integrations: messaging, REST/GraphQL, event-driven. * Understanding of resilient architectures and high availability. * Familiarity with security standards (NIS2). Behavioral Skills: * Excellent analytical and synthesis skills. * Structured and pedagogical communication. * Global vision and ability to maintain an overview. * Quality orientation, autonomy, and proactivity. * Ability to connect business needs with technical challenges. Education: Master's degree in Computer Science or equivalent experience. Language Skills: Very good command of French, Dutch, and English., * Agile / Scrum level expert - Level: Confirmed - Most recent: Any time * Altassian Stack level confirmed - Level: Confirmed - Most recent: Any time * Angular / ReactJS - Level: Confirmed - Most recent: Any time * Docker/ JSF/ SonarQube/SOAP/Swagger/ OpenAPI/ Openshift Level Confirmed - Level: Confirmed - Most recent: Any time * Exprience au sein dun service public fdral - Level: Confirmed - Most recent: Any time * Hexagonal Architecture Level Confirmed - Level: Confirmed - Most recent: Any time * IntelliJ Level Expert - Level: Confirmed - Most recent: Any time * Java Level Expert - Level: Confirmed - Most recent: Any time * Jira / Confluence - Level: Confirmed - Most recent: Any time * JUnit/ SQL / Flyway Level Expert - Level: Confirmed - Most recent: Any time * Lombok Level Confirmed - Level: Confirmed - Most recent: Any time * Maven/Git/Rest Level Expert - Level: Confirmed - Most recent: Any time * NPM/ IBM websphere Level Confirmed - Level: Confirmed - Most recent: Any time * Spring/ spring boot Level Expert - Level: Confirmed - Most recent: Any time ## Description Keystone Solutions is seeking a Senior Fullstack Java Developer for a consultancy mission at a client site. The organization operates in a complex technological environment, combining a historical application landscape with modern components. This role involves participating in a structural transformation of the IT landscape, modernizing architectures, reducing technical debt, adopting Cloud solutions, and ensuring compliance with regulations, including NIS2. The existing applications cover critical areas such as unemployment regulation, payments, debt management, and financial and accounting processing. Some of these systems rely on legacy technologies, while new Cloud/hybrid architectures are emerging. The architect plays a key role in harmonizing, securing, and aligning these architectures., As a consultant representing Keystone Solutions, you will carry out the following responsibilities: * As a Programmer: Develop and/or adapt IT applications to provide efficient and user-friendly tools for end-users. * As an Analyst-Programmer: Analyze the technical specifications of an application to choose the best solution and execute this analysis (for smaller projects) to enable users to perform their tasks efficiently and ensure the optimal and controlled functioning of IT resources. * As a Specialist: + Conduct technical analyses within business projects. + Advise on integrations, data models, performance, and scalability. + Support the team in adopting technologies and architectural patterns. + Analyze and resolve complex technical issues in a highly interconnected environment. + Ensure coherence between legacy and modern components. ## Related Videos - [Navigating the Corporate Jungle: Life as a Developer in a large Company](https://www.wearedevelopers.com/videos/621-navigating-the-corporate-jungle-life-as-a-developer-in-a-large-company) - [How Unit Testing Saved My Career](https://www.wearedevelopers.com/videos/1642-how-unit-testing-saved-my-career) - [Improving quality with Agentic AI with Rovo Dev and Xray](https://www.wearedevelopers.com/videos/2005-improving-quality-with-agentic-ai-with-rovo-dev-and-xray) - [How a Small Team Shrank a Microsoft Monorepo by 94%](https://www.wearedevelopers.com/videos/1236-how-a-small-team-shrank-a-microsoft-monorepo-by-94) - [From boy scouting to redrawing the landscape](https://www.wearedevelopers.com/videos/1140-from-boy-scouting-to-redrawing-the-landscape) - [Integrate your Cognitive Assistant with 3rd-party DBs and software](https://www.wearedevelopers.com/videos/249-integrate-your-cognitive-assistant-with-3rd-party-dbs-and-software) ## Related Articles - [What’s the Difference between a Junior, Mid, and Senior Developer?](https://www.wearedevelopers.com/magazine/238-what-s-the-difference-between-a-junior-mid-and-senior-developer) - [Software Developer Salary in The Netherlands [2023]](https://www.wearedevelopers.com/magazine/217-software-developer-salary-in-the-netherlands-2023) - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again) - [Why Upskilling And Reskilling is Important For Developers](https://www.wearedevelopers.com/magazine/428-why-upskilling-and-reskilling-is-important-for-developers) - [Fullstack developer salary in Germany [2023]](https://www.wearedevelopers.com/magazine/197-fullstack-developer-salary-in-germany-2023) - [Is Software Engineering Over-Saturated?](https://www.wearedevelopers.com/magazine/418-is-software-engineering-over-saturated)