Features and Feature Stores — Where Fraud ML Is Actually Won
Ask practitioners where fraud detection quality comes from and the answer is uniform: not the model — the features. Velocities, histories, graph signals, and their freshness carry the signal; the model just reads it. And ask where production fraud ML fails and the answer is equally uniform: the gap between how features were computed in training and how they're computed at serving time. This post covers both — the feature families that catch fraud, and the feature-store discipline that keeps them honest.
Signal lives in velocities (second-fresh streaming aggregates), histories, precomputed graph neighborhoods, and composed scores. The characteristic failure is training/serving skew — feature time-travel leaking the future into training. The feature store fixes it by construction: one event-time definition, two materializations.