Principal Engineer (m/f/d) Seller Domain

Overview

Your Mission As a Principal Software Engineer, you will be responsible for leading the design and implementation of the domain architecture for Seller Experience. This is one of Ratepay's four core domains and you will be responsible for the seamless commercial & technical integration and fast onboarding of sellers, such as merchants, marketplaces or resellers. You will play a critical role in shaping the technical direction of the company and ensuring that our systems are scalable, reliable, and easy to maintain. Additionally, you will be responsible for fostering cross-domain collaboration and alignment to ensure that our systems are fully integrated and able to meet the needs of our customers.

Key Responsibilities

• Lead the design and implementation of the domain architecture for our software systems
• Ensure that our systems are scalable, reliable, and easy to maintain
• Foster cross-domain collaboration and alignment to ensure that our systems are fully integrated
• Make technical decisions and provide guidance to the development team
• Work with the business stakeholders and other members of the development team to understand the requirements and make technical decisions that align with the overall architecture and strategy
• Work with the tech teams to ensure that the applications are optimized for the cloud
• Extend existing APIs to improve functionality and performance
• Stay up to date with the latest technologies and trends in the industry and bring new ideas to the team

Qualifications

• Bachelor's degree in Computer Science or related field
• 10+ years of experience in software development, with a focus on Java or Kotlin
• Strong experience with domain-driven design and architecture
• Strong understanding of Java, Kotlin, Spring, and related technologies
• Experience with Fintech
• Experience with AWS
• Experience integrating applications with Salesforce
• Experience with microservices architecture and RESTful APIs
• Experience designing and building customer- and merchant-facing APIs and SDKs
• Experience building and maintaining comprehensive documentation to support merchant integrations

Equal Opportunities & Diversity

We value our diversity and welcome everyone to our team. Regardless of ethnic and social background, religious views, worldview, gender, sexual orientation, physical and mental limitations, age, marital status, educational background and nationality. With over 200 employees and 40 different nationalities we take our values seriously. These include; ownership, growth, integrity, collaboration, customer centricity and inclusion.

About Us

We dare to design the future of payments, together. Born in the heart of Berlin’s fintech hub, Ratepay has passionately crafted tomorrow’s payment solutions for over a decade. Today, we’re proud to be Europe’s leading white-label Buy Now, Pay Later provider, trusted by brands like Eurowings, ZARA, and PUMA. Our success comes from teamwork, openness, and continuous improvement. We value shared goals over egos, fostering a culture of courage, commitment, and warmth. Our dedicated team of 200+ professionals powers the entire payment value chain - from integration to AI-driven risk management and dunning – delivering tailored payment solutions for businesses across Germany, Austria, Switzerland, and beyond. At Ratepay, we never stop improving — our products, our processes, and ourselves. Ready to transform commerce payments with us?