  With the explosive growth of e-commerce and the booming of e-payment,
detecting online transaction fraud in real time has become increasingly
important to Fintech business. To tackle this problem, we introduce the TitAnt,
a transaction fraud detection system deployed in Ant Financial, one of the
largest Fintech companies in the world. The system is able to predict online
real-time transaction fraud in mere milliseconds. We present the problem
definition, feature extraction, detection methods, implementation and
deployment of the system, as well as empirical effectiveness. Extensive
experiments have been conducted on large real-world transaction data to show
the effectiveness and the efficiency of the proposed system.
