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02Credit Risk · ML · Decision Intelligence

Sentinel Credit.

An end-to-end BNPL risk intelligence platform for thin-file customers, combining modelling, monitoring, explainability and governance.

Role
Data Scientist / ML Engineer
Stack
Python · SQL · XGBoost · AWS · MLflow · Airflow · SHAP
Status
Portfolio case study
Green glass bars of rising height with a gold trend line and a gold score gauge

01 · Problem

Thin-file lending creates a decision problem, not just a modelling problem.

Customers with limited bureau history can be difficult to assess using conventional signals. The project explores how behavioural, affordability and repayment evidence can be combined without hiding uncertainty.

02 · Approach

Model the customer journey, then engineer the decision.

A synthetic BNPL environment was designed around customer, application and repayment grains, followed by feature engineering, challenger models, affordability logic, explainability, monitoring and governance controls.

03 · Decisions

Designed for trade-offs, not demos.

Natural keys and shared SQL features were chosen to preserve consistency across training and inference. Thresholds are treated as business decisions rather than defaulting to 0.5, and model outputs are separated from policy rules.

04 · Evidence

Performance is only useful when it survives deployment.

The evaluation plan includes discrimination, calibration, temporal validation, drift monitoring, fairness checks and challenger comparison. Thresholds are linked to affordability and risk appetite rather than selected in isolation.

05 · Reliability

Trust is part of the architecture.

The design includes human approval points, SHAP-based explanations, drift triggers, lineage and monitoring. Synthetic data is clearly separated from real customer evidence to avoid false claims of production performance.

06 · Reflection

Better simulation changed the whole project.

The data generator evolved into a hazard-based state machine because simplistic synthetic defaults produced unrealistic patterns. That redesign improved the credibility of both model development and monitoring.

System architecture

Synthetic BNPL data
Feature store
Risk models
Decision policy
Monitoring
  • Credit Risk
  • Thin-file
  • XGBoost
  • SHAP
  • Drift
  • Governance