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Flatpay is a fast-growing payment company expanding into online payments. As a Senior Software Engineer on the Online team, you'll help define the technical direction of Flatpay's online platform and establish the architectural foundations for the next phase of growth.
This is an early-stage opportunity within a scaled company. While Flatpay already serves merchants at scale, the online platform is still in its early stages. You'll launch new solutions, shape platform evolution as adoption grows, and learn directly from customers.
Key responsibilities:
- Design and build scalable systems powering online payments and commerce experiences
- Lead feature and platform initiatives involving multiple engineers, driving delivery from discovery through production
- Own features from design and implementation through deployment and maintenance
- Drive architectural decisions and long-term technical improvements
- Build APIs, services, and integrations enabling online payment experiences
- Improve reliability, observability, performance, and security across the platform
- Partner with engineers, product managers, and stakeholders on technical and product outcomes
- Mentor engineers through coaching, code reviews, and knowledge sharing
- Help establish engineering standards and best practices as the Online domain grows
You'll work with backend technologies including Java, Spring Boot, MySQL, REST APIs, event-driven architecture, and domain-driven design. Frontend work involves TypeScript, React, TanStack Query, Jest, and Playwright. Platform and delivery tools include GitHub Actions, CI/CD, and AWS ECS with observability and monitoring.
Flatpay operates from a Copenhagen office with an emphasis on close collaboration, quick feedback loops, and side-by-side problem-solving. The company offers perks including on-site gym, gamer room, and other benefits.
Requirements:
- 7+ years of professional software engineering experience
- Strong experience designing and operating distributed systems
- Demonstrated ability to lead technical projects involving multiple engineers and influence architectural decisions
- Experience building scalable backend platforms and APIs
- Comfortable navigating ambiguity and helping shape new products and systems
- Strong communication and collaboration skills
- Experience within payments, fintech, e-commerce, SaaS, or high-scale transaction systems is a plus
