Senior Fraud ML Validator & AI Risk Lead

Klarna; Greater London; On-site; GBP 70,000 - 100,000; Full time

Benefits offered by this job

Hybrid office presence 2-3 days/wk

Job summary

Klarna is seeking a second-line validator for fraud models to ensure robustness against real-time attacks across payments, logins, and identity. You will reproduce results, stress-test pipelines, and validate governance and privacy aspects.

You will work with scikit-learn, LightGBM, graph models, anomaly detection, and GenAI components, while building tooling to surface risks automatically and support model risk governance.

Qualifications

• 3+ years hands-on fraud-related modeling (transactions, accounts, identity).
• Experience with tree-based models (LightGBM) and anomaly/graph approaches.
• Full ML lifecycle experience from feature engineering to production monitoring.

Responsibilities

• Assess model performance using fraud-specific metrics and assess business trade-offs.
• Review large transaction datasets and feature pipelines for leakage and bias.
• Evaluate drift detection, retraining, and production monitoring practices.

Skills

Fraud modeling

LightGBM

Graph models

Anomaly detection

GenAI workflows

Education

Master's or PhD in quantitative field

Tools

Python

SQL

PySpark

Job description

Klarna is seeking a second-line validator for fraud models to ensure robustness against real-time attacks across payments, logins, and identity. You will reproduce results, stress-test pipelines, and validate governance and privacy aspects.

You will work with scikit-learn, LightGBM, graph models, anomaly detection, and GenAI components, while building tooling to surface risks automatically and support model risk governance.