Senior / Expert Java Developer

Senior / Expert Java Developer Senior/Expert Java Developer for bank backend: design, build and modernize microservices and integrations; lead, mentor, and deliver in a hybrid Poland setup. Senior / Expert Java Developer About the Client Our client is a major international player in the banking industry. You will be joining their IMSecurities department, contributing to a large-scale technological transformation involving the migration of massive business flows and volumes projected through 2027–2029. The Role We are looking for a Senior or Expert Java Developer to design, build, and modernize backend integration components for a core Safekeeping and Corporate Actions platform. You will be joining an expanding, agile team (scaling from 8 to 15 developers), working hands-on with the code while occasionally stepping up to lead analysis and deployment orchestration. What You Will Do Design, develop, test, deploy, and support Java-based microservices and integration components. Connect internal security systems with other banking infrastructure using event-driven architectures. Analyze business requirements, document dependencies, and troubleshoot complex production issues. Contribute to the team's growth by sharing knowledge, promoting best development practices, and mentoring junior colleagues. Work in a Scrum environment (JIRA), filling in the blanks in requirement analysis and test case preparation when bottlenecks occur. Expectations Experience: Min. 5 years (for Senior) or 10+ years (for Expert) of Java backend development in large-scale enterprise environments. Core Stack: Java, Spring Boot, Spring Integration. Architecture & Integrations: REST services, microservices, and integration patterns. Messaging: Event-driven integration platforms (preferably IBM MQ and Kafka). Databases: Strong SQL and relational database knowledge (preferably Oracle). DevOps & Testing: Maven, Git, CI/CD pipelines, and automated testing (JUnit, Testcontainers). Languages: Fluent English (both written and spoken). Nice to Have Previous experience in banking, trading, custody, settlement, or other regulated domains. Familiarity with cloud-ready application design and containerization (Kubernetes). Experience modernizing legacy systems or building layers around vendor platforms. Practical use of AI-assisted development tools and static code analysis. What We Offer Salary: 140 - 170 PLN / hour (B2B). Type of Work: Hybrid (50% remote / 2-3 days a week in the office). Location: Gdańsk or Warsaw. Specjalizacja / specialism IT Role BackEnd Developer Locations Warsaw , Gdańsk Remote status Hybrid About OPTIVEUM sp. z o.o. Optiveum is a recruitment and consulting company created based on our 20-plus years of experience in HR & IT services. We work for Clients located in Poland and abroad providing our local and international Candidates with Project-based or Permanent job opportunities in a remote or office-based model. COMPANY DATA Optiveum Sp. z o.o. ul. Tomasza Zana 43 lok. 2.1 20-601 Lublin, Poland nr KRS: 0000834436, NIP 7010975729 Contact us at: info (at) optiveum.com