What you will do You will design, build, and maintain scalable Python applications across backend services, APIs, and data infrastructure, developing and optimising RESTful APIs and microservices using frameworks such as FastAPI, Django, or Flask. You will build and maintain data pipelines, ETL processes, and integrations with both SQL and NoSQL databases, while collaborating with data science and ML teams to productionise models and automate workflows. Contributing to architectural decisions and technical roadmaps, you will write clean, well-tested, and well-documented code and participate in thorough code reviews. You will also mentor junior and mid-level engineers, fostering a culture of technical excellence, and identify and resolve performance bottlenecks, bugs, and reliability issues across the platform. Who you are 5+ years of professional Python development experience, with a deep understanding of Python internals, async programming, and performance optimisation. Strong experience with at least one web framework such as FastAPI, Django, or Flask. Hands-on experience with data tools such as Pandas, NumPy, SQLAlchemy, or Airflow. Experience with AWS and containerisation technologies including Docker and Kubernetes. Proficiency with CI/CD pipelines, Git workflows, and testing frameworks such as pytest. Strong grasp of software design patterns, SOLID principles, and clean architecture. Excellent communication and collaboration skills. Awesome to have Experience with DevOps tooling and infrastructure-as-code solutions such as Terraform or Ansible. Background in distributed systems or event-driven architecture using Kafka or RabbitMQ. Familiarity with ML/AI libraries such as scikit-learn, PyTorch, or TensorFlow. Contributions to open-source Python projects. Please include a CV in English Curious to learn more about Klarna and what it's like to work here? Explore our career site!