Madiff

Senior Principal Java Developer

Madiff  •  Warsaw, PL (Hybrid)  •  4 months ago
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Job Description


We are looking for a Senior Principal Java Backend Developer to join a mission-critical backend platform operating at enterprise scale. The role is focused on hands-on backend development within a high-volume, production-critical fintech environment, with additional responsibility for mentoring engineers and supporting technical alignment across the team. The work involves building and maintaining core services supporting transaction processing, financial reporting, and merchant-facing functionality under strict security, availability, and performance requirements.
Responsibilities

  • Design, develop, and maintain backend services using Java 17+

  • Build scalable microservices supporting high transaction volumes
    and real-time processing

  • Integrate backend services with Oracle databases, internal
    financial systems, and external APIs

  • Ensure security, performance, and reliability aligned with fintech
    standards

  • Collaborate closely with product managers, architects, and analysts

  • Contribute to architectural decisions and platform modernisation

  • Support production deployments, monitoring, and troubleshooting

  • Mentor junior engineers and raise engineering standards

  • Participate actively
    in code reviews and quality initiatives


Requirements


  • Minimum 5 years of commercial Java backend experience

  • Strong expertise with Java 17+

  • Hands-on experience with Oracle, SQL, and PL/SQL

  • Solid experience with microservices and REST APIs

  • Strong understanding of clean architecture and design patterns

  • Experience working in Agile delivery teams

  • High ownership mindset
    and strong communication skills
    Nice to have

  • Experience in fintech, payments, or banking
    environments

  • Exposure to CI/CD, DevOps, and containerised
    environments

  • Previous technical
    leadership or Team Lead experience


Benefits


  • Solid, competitive salary

  • Work in multinational environment on international projects

  • Comprehensive healthcare

  • Long-term B2B contract with stable project pipeline

  • Hybrid work model
Madiff

About Madiff

We are an international Innovation, IT and high-tech engineering consulting company that delivers unique value in a wide variety of industries.

Our mission is to add value to our customers businesses by providing digital and technological innovation services, delivering disruptive results and making our clients stand out in their market.

We are driven by a creative and innovative consulting approach strongly oriented to getting results. We MAKE THE DIFFERENCE.

Poland | UK | Switzerland | USA | Norway | Portugal | Spain | France | Singapore

Warsaw

Prosta 20

Wrocław

Rybacka 7

Lublin

Grottgera 2

Industry
IT & Software
Company Size
51-200 employees
Headquarters
Warszawa, PL
Year Founded
2015
Website
madiff.eu
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