Senior Polyglot Engineer

We’re building Klarna’s next-generation money movement engine — a cross-platform system enabling fast, secure, and seamless money transfers across markets, currencies (including crypto), and payment networks. This engine will be a native part of Klarna’s core consumer products and help the company evolve from a BNPL provider to a borderless neobank.

You’ll work alongside product, design, compliance, and other engineering teams to deliver high-performance financial experiences at global scale.

We offer a hybrid work model in Warsaw’s vibrant Wola district. English fluency and eligibility to work in Poland are essential, as is the successful completion of a background check to meet the rigorous standards of the financial domain.

Requirements:

• 8+ years of experience in software development, with strong backend focus
• Proficiency in Java, Node.js, Python, and TypeScript
• Experience building scalable, fault-tolerant backend services and APIs
• Familiarity with payment integrations, banking/crypto APIs, and compliance (KYC/AML)
• Experience with PostgreSQL, Redis, and AWS services
• Understanding of CI/CD pipelines and monitoring best practices
• Bonus: experience contributing to frontend codebases using React or React Native
• Bonus: Klarna ecosystem experience (payments flow, internal services)

Main responsibilities:

• Design, implement, and maintain robust backend systems and APIs powering P2P and cross-border transfers
• Own features end-to-end: from system architecture and development to deployment and monitoring
• Integrate with external payment and banking APIs, ensuring secure and compliant transaction flows
• Collaborate with Klarna-internal systems (payments, identity, customer support
• (Optional) Contribute to frontend development for AI-enhanced money transfer interfaces, FX tracking, and transaction histories
• Ensure high standards in observability, fault tolerance, and security
• Mentor junior engineers and contribute to internal documentation and knowledge sharing