Backend Java Developer f m w Warszawa, Polska

Java Developer We are looking for an experienced Backend Java Developer to join an international team developing systems for savings and investment products. The applications support areas such as taxation, account management, and investment processing. Responsibilities Design, develop, and maintain backend applications using Java. Develop solutions supporting savings and investment products. Build robust calculation engines compliant with tax regulations across multiple countries. Implement complex business processes and integrations with external institutions, including tax authorities. Develop customer-facing reporting functionalities. Participate in the full software development lifecycle, including requirements analysis, design, coding, testing, and deployment. Cooperate with financial analysts to translate business requirements into technical solutions. Conduct code reviews, mentor other developers, and contribute to technical design decisions. Promote practical engineering standards and best practices across the team. Use AI-assisted development tools and automation responsibly to improve productivity, quality, and continuous learning. Requirements Strong commercial experience with Java and Spring Boot. Practical experience with Hibernate. Very good knowledge of relational databases, particularly PostgreSQL and SQL. Experience in designing and developing APIs using OpenAPI. Practical knowledge of Apache Kafka or similar messaging technologies. Understanding of reliable message processing, including retries, idempotency, error handling, dead-letter queues, message ordering, and monitoring. Experience with Jenkins and CI/CD processes. Very good knowledge of Git. Ability to model complex business logic and design maintainable solutions. Experience in software testing and ensuring high code quality. Readiness to conduct code reviews, mentor developers, and act as a design sparring partner. Ability to cooperate effectively with analysts and business stakeholders. English proficiency sufficient for daily work in an international environment. Nice to Have Experience in the banking, financial services, investment, or pension sector. Knowledge of AsyncAPI, JMS, or MQ. Experience developing calculation engines or systems based on complex business rules. Practical and responsible use of AI-assisted software development tools. Experience with Java 21. What We Offer Long-term cooperation in a strategic project. Work on solutions used across multiple international markets. Real influence on architecture, code quality, and engineering standards. A role combining hands-on development with mentoring and technical decision-making. Cooperation within a mature, international environment. Modern technology stack, including Java 21, Spring Boot, PostgreSQL, APIs, and messaging. Cooperation Details Contract type: B2B Work model: Hybrid Office presence: 3 days per week Location: Warsaw or Gdańsk Project language: English Recruitment interview: Conducted in English Applications: Reviewed on an ongoing basis Important: The work must be performed from Poland; working from abroad is not possible.