Senior Python Engineer -FinCrime

Klarna
Klarna

Software Engineering

Milan, Italy

Posted on Jun 23, 2026
What you will do You will own Python services end-to-end — designing, building, shipping, and operating Lambdas and APIs that Klarna's investigation agents depend on around the clock. Working within a distributed system of Python Lambdas, Kafka streams, REST APIs, Elasticsearch clusters, and DynamoDB tables, you will reason across a fleet of services and keep a current understanding of how dozens of components hand off work via SNS topics, SQS queues, and API calls. You will debug across service boundaries, tracing individual orders or banking events through multiple layers to pinpoint issues using CloudWatch Logs and Datadog. A key part of your contribution will be translating between business and engineering, absorbing requirements from risk, product, and CX stakeholders, turning them into concrete designs, and communicating outcomes clearly to non-technical audiences. You will also master the messaging patterns that underpin the platform, including SNS fan-out, SQS with DLQs, idempotency, and back-pressure handling. Who you are Proficient in Python 3.11+, with production experience in async code and typed models using Pydantic. Experienced with FastAPI or an equivalent Python web framework, including authentication, validation, and operating behind API Gateway. Hands-on with AWS serverless technologies including Lambda, SNS, SQS with DLQs, API Gateway, CloudWatch, IAM, and DynamoDB. Skilled in operating Elasticsearch at scale, including query DSL, index lifecycle management, and cluster tuning. A strong communicator who can work directly with non-technical stakeholders, understand their needs, and explain technical outcomes in plain language. A wesome to have Familiarity with TypeScript and React, with the ability to trace bugs into a frontend codebase and make small changes. Working knowledge of Java, enabling cross-team debugging with upstream services. Experience with Kafka streams and event-driven architecture patterns. Background in platform or infrastructure engineering within a distributed systems environment. Please include a CV in English Curious to learn more about Klarna and what it's like to work here? Explore our career site!