Senior Machine Learning Engineer - Credit modelling

Klarna; Milano; Hybrid; EUR 90,000 - 130,000; Full time

Job summary

Klarna is seeking a Lead Engineer for the Credit Modeling Pipeline to transform consumer credit underwriting models from experiments into production-ready systems. You will write production-grade Python, build the ML infrastructure, and deploy models using AWS SageMaker, ensuring reliability in production.

You will work with a cross‑functional team across Stockholm and Warsaw, with a split base in Milan or Stockholm per location, and help scale Klarna’s in‑house data science capability as the

Qualifications

• Production Python for ML
• Takes ML models to production and owns them
• Hands-on with tree-based models
• Deploys ML workloads on cloud platforms (AWS or similar)
• Follows full SDLC for ML code and workflows
• Collaborates with data scientists to build reliable pipelines
• Communicates effectively in English (spoken & written)

Responsibilities

• Write Python to train credit underwriting models and prepare them for production.
• Build and maintain infrastructure for the ML pipeline, from feature computation to retraining and monitoring.
• Deploy models into production using AWS SageMaker and keep them running.
• Troubleshoot and fix pipeline issues end to end.
• Scale Klarna's in-house data science capability as credit risk and fraud teams grow.

Skills

Python

ML deployment

AWS SageMaker

CI/CD for ML

Production-grade code

Tree-based models

Tools

AWS SageMaker

Job description

Klarna, brieflyAt Klarna, we're building an everyday finance network, helping over 120 million consumers across 26 countries save time and money, and worry less about their finances. Working here means taking on problems most companies never get to solve, and being hands‑on enough that the interesting part of the work lands with you, not someone else — you'll build with AI, not watch it happen.

This is the stretch zone. Come find out what you're capable of.

About The Role

Every credit decision Klarna makes runs through a model, and every one of those models runs through a pipeline your team builds and operates. As a Lead Engineer on the Credit Modeling Pipeline team, you'll be the engineer who takes consumer credit underwriting models from a data scientist's experiment to something running reliably in production.

This is an engineering position, not a data science one with some engineering on the side. Most of your time goes into writing production code, building the infrastructure the ML pipeline depends on, and deploying models with tools like AWS SageMaker — not developing new modeling approaches from scratch.

You'll work alongside a team split between Stockholm and Warsaw, and help scale Klarna's in-house data science capability as the credit risk and fraud teams grow.

What You'll Do

• You'll write Python to train credit underwriting models, including tree-based models, and prepare them to run in production.
• You'll build and maintain the infrastructure that supports the ML pipeline — from feature computation through to retraining and monitoring.
• You'll deploy models into production using tools such as AWS SageMaker, and keep them running once they're live.
• You'll troubleshoot and fix pipeline issues end to end, rather than handing them off to someone else.
• You'll help scale Klarna's in-house data science capability as the credit risk and fraud teams grow.

Who You Are

• You've written production Python for machine learning — training models, not just prototyping them in notebooks.
• You've taken machine learning models and pipelines from development into production, and owned them once they were live.
• You've worked with tree-based models hands‑on, not just studied them in theory.
• You've deployed and operated ML workloads on AWS or a comparable cloud platform.
• You understand the full software development lifecycle — version control, testing, and code review — and apply it to ML code, not just one-off scripts.
• You've worked closely with data scientists, turning their models into pipelines they can rely on in production.
• You communicate clearly in English, spoken and written.

Bonus points for

• You've worked in credit risk, fraud, or another part of financial services, and know the regulatory weight that comes with lending decisions.
• You've built data pipelines at scale inside a larger data science or engineering organization.
• You're familiar with model monitoring or observability tools — drift detection, performance dashboards, and the like.
• You've set up CI/CD for ML deployment.

Things you should know before applying

• This position is based in Stockholm or Milan; you'll work alongside a team split between Stockholm and Warsaw.
• Working together: we value co-located teams; most teams currently meet in the office 2–3 days per week, and this varies by team and can change over time.
• Non-obvious backgrounds are welcome. Diversity of skills, perspectives and backgrounds is how we create, innovate, and disrupt like no other.
• Final compensation will be based on the candidate's qualifications, skills, and experience.