How do you help make a difference? As a Senior Java Developer – Commercial channels and products (Doli), you contribute to the design, development, and maintenance of backend components and RESTful APIs supporting enterprise-grade applications within SNCB/NMB. You ensure that backend services are robust, scalable, and maintainable, contributing directly to reliable digital services that support operational and customer-facing systems. Your scope covers backend services, integrations, and APIs, working closely with architects, analysts, DevOps engineers, and development teams. As a Senior Java Developer, you will take on the following responsibilities: 1. You design, develop, and maintain backend services and REST APIs using Java and Spring Boot. 2. You ensure code quality through unit, integration, and performance testing. 3. You conduct code reviews, promote best practices, and mentor junior developers. 4. You collaborate with architects, analysts, and DevOps engineers to define and refine technical solutions. 5. You support deployment, cutover, and hypercare phases, ensuring stable releases. 6. You troubleshoot and resolve production issues, ensuring system performance and reliability. Why is this job a good fit for you? You have proven experience in Java development and backend engineering, with extensive exposure to enterprise environments, microservices, and integration-heavy systems. You have a minimum of 10 years working experience as a Java developer. 7. You have demonstrable experience of minimum 5 years with microservices architecture. 8. You have demonstrable experience of minimum 5 years with SOAP. 9. You have proven experience of minimum 5 years in building cash desk tools used at service counters to sell tickets, manage operator sessions, and handle cash transactions. 10. You have 5 years of experience integrating hardware components into IT systems, such as payment terminals, scanners, and printers. 11. You have a minimum of 5 years of experience in the public transport sector, with strong understanding of ticketing, sales, and operational processes. 12. You have demonstrable experience of minimum 3 years with the Spring framework. 13. You use core Java concepts effectively, including OOP, collections, streams, and exception handling. 14. You apply Spring Boot, JPA/Hibernate, Maven or Gradle, and testing frameworks. 15. You design clean, reusable REST APIs, respecting standards and security. 16. You have experience with CI/CD pipelines, Git, Docker, and Kubernetes. 17. You have solid knowledge of SQL and NoSQL databases, caching, and messaging systems such as Kafka and RabbitMQ. 18. You are familiar with monitoring, logging, and observability tools such as Prometheus, ELK, and Grafana. You have excellent problem-solving skills and attention to detail. 19. You are able to own complex technical challenges. 20. You communicate effectively and work well in a team within an Agile/Scrum delivery environment. 21. You are fluent in English and it’s a plus if you have knowledge of Dutch or French Everyone is unique. That's why we believe it’s important that you can be yourself — it makes Ypto and SNCB/NMBS stronger. We therefore place great value on diversity and inclusion. Choosing Ypto means choosing to contribute to the digital transformation of the Belgian railways. You will have a job with social impact and ample opportunity to make your own contribution. Alongside a healthy work-life balance and a competitive salary, we offer: Hybrid working, with a balanced weekly mix of office and remote work, combined with flexible hours. 35 days of annual leave. A mobility package with a company car (also available via our mobility plan) or alternative mobility choices, complemented by a public transport season ticket. A target bonus. A comprehensive insurance package, with hospitalisation and dental care for the whole family. Coverage of outpatient medical costs. Group insurance, including a supplementary pension (cafeteria plan). Meal vouchers & eco vouchers. Net allowances for hybrid working and an internet allowance. You will work near Brussels-South station and also from home (remote). You apply online. We take a close look at your CV and check whether it matches the profile you are looking for. We may call you briefly to ask about your motivation and experience. We invite you for a first (online) HR interview where you can demonstrate your motivation, experience and expectations. If the first interview is positive, we invite you for a second (technical) interview in Brussels. This interview will be with the team, where we’ll discuss the role and how your skills align with the team’s needs. If everything goes well, we will make you a contract offer. You start your new job! We reserve the right to adjust or pause this procedure if necessary. Our recruitment team will select the profiles that best match the job requirements to ensure an optimal fit. Ypto recruitment Mail: style="min-height: