Java Backend Developer at Madiff – Warsaw | Jobyssey

We are looking for a Java Backend Developer to join a production-critical backend platform within the payments domain. The role focuses on building and maintaining high-performance backend services in a regulated, high-scale environment, supporting transaction processing, settlements, financial reporting, and integrations with internal and external systems. Strong hands-on Java experience and comfort working with mature, mission-critical systems are essential.

Responsibilities

Design and develop backend services using Java 17+
Build scalable components supporting transaction data, settlements, and reporting
Integrate backend services with relational databases and internal financial systems
Develop secure REST APIs aligned with compliance and security standards
Collaborate closely with product owners, analysts, architects, and QA teams
Optimise system performance, reliability, and data processing efficiency
Participate in code reviews, testing, and continuous improvement activities
Support platform modernisation and resolve production issues
Contribute to clean code practices and long-term platform scalability

Requirements

3–5 years of commercial Java backend experience
Strong knowledge of Java 17+ and modern backend frameworks
Hands-on experience with relational databases (SQL; Oracle / PL/SQL preferred)
Experience working with microservices and distributed systems
Solid understanding of REST API design and system integrations
Experience working in Agile delivery teams
Good communication skills and ability to work in international environments

Nice to have
Experience in fintech, payments, banking, or other regulated domains
Exposure to CI/CD pipelines, DevOps practices, or containerised environments
Experience with messaging or event-driven architectures
Background in high-volume or real-time systems

Benefits

Solid, competitive salary
Work in a multinational environment on international projects
Comprehensive healthcare
Long-term B2B contract with a stable project pipeline
Hybrid working model (remote with 1 day per week in the Warsaw office)

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