Full Stack Developer (Java)

For our Client we are looking for a Full Stack Java Developer. Warsaw, hybrid (4 days per week from the office) B2B: 28,000–35,000 PLN per month Key Responsibilities • Gather and analyse requirements with business stakeholders • Design, plan, implement and test changes with the engineering team • Adapt and enhance legacy Java applications for ISO 20022 changes • Develop and maintain backend services and integrations • Participate in code reviews, UAT support and production releases • Continuously improve code quality and system design Requirements • 4+ years of experience as a Java / Full Stack Developer • Strong hands-on experience with: Java, Spring, Spring Boot (DI, Spring Data, Spring Security) • Hibernate, DB2 • Apache Kafka (producers, consumers, Kafka Streams, Kafka Connect) • MongoDB (document modelling, Spring Data MongoDB) • RESTful APIs, microservices, event‑driven architectures • Maven (multi-module builds) • Docker • Git & CI/CD (GitLab CI preferred) • Experience working in distributed systems and complex legacy codebases • Strong analytical skills and ability to understand complex business logic • Good communication skills and ability to work in a global team