Senior / Expert Java Developer / Architect (f/m)

We are looking for an experienced Java Developer / Architect to join a long-term project within the financial systems domain. The project focuses on a major platform modernization, including the development of new functionalities, architectural transformation, legacy code refactoring, and the development of modern integration microservices. Location & Work Model Warsaw or Gdańsk Hybrid work – 2 days per week from the office International working environment English as the working language We are looking for both Senior (5+ years of experience) and Expert (10+ years of experience) profiles MUST-HAVE Java Spring Boot Spring Integration Oracle / SQL Kafka / IBM MQ REST API Jenkins Maven Git JUnit Testcontainers Experience with microservices architecture and enterprise-scale systems NICE-TO-HAVE Experience in the banking or financial sector AWS Docker / Kubernetes Experience working with legacy code Selenium Responsibilities Designing and developing backend integration components in Java Developing microservices based on Spring Boot Integrating systems using REST API, Kafka, and IBM MQ Modernizing existing solutions and refactoring legacy code Analyzing business and technical requirements Analyzing logs and data flows and troubleshooting production environments Developing and maintaining automated tests using JUnit and Testcontainers Participating in deployments and supporting releases Performing code reviews and promoting software development best practices For Expert-level candidates: mentoring less experienced developers About the Project This is a long-term initiative focused on modernizing a large-scale financial platform. The upcoming years will involve the migration of business processes and volumes, combining the development of new solutions with significant architectural modernization and legacy code refactoring. The team is expanding significantly. The number of developers is expected to grow from approximately 8 to 15, while the broader area will include more than 35 specialists across Development, QA, Business Analysis, and Infrastructure Engineering. The team works in Scrum and uses JIRA. What Makes This Project Attractive? Long-term, strategic project Modern backend stack based on Java, Spring Boot, and Kafka Hands-on work with microservices architecture Real influence on the architecture of the system Strong focus on designing and building new solutions rather than maintenance only Opportunity to work at an expert level and mentor other developers Large-scale systems and a stable working environment International collaboration in English Opportunity to develop expertise in enterprise integrations and financial systems