Predictive Modeling & Transaction Audit System for Financial Platform

A robust AI system for behavioral prediction and quantitative analysis of customer transactions, with comprehensive audit capabilities for payout and balance calculations in financial services.

Project Goal

For a client in the financial services space, the project aimed to develop a robust AI system for behavioral prediction and quantitative analysis of customer transactions, along with a comprehensive audit of payout and balance calculations. The objective was twofold:

  • Detect potential fraud and collusion by modeling user behavior across large datasets.
  • Guarantee transaction and payout accuracy for a new suite of financial products, ensuring correctness even in highly complex edge cases.

Challenges

This project came with a unique set of challenges:

  • Domain Expertise Barrier: The work began with no prior knowledge of the client's specific transaction domain. Critical concepts—ranging from product mechanics to academic research on strategic customer behavior—had to be absorbed quickly.
  • Massive and Unstructured Data: The data consisted of hundreds of gigabytes of raw JSON logs detailing millions of transactions. This required efficient data processing pipelines and custom-built parsers to convert data into a usable format.
  • High-Stakes Accuracy: The audit had zero tolerance for miscalculation. Edge-case complexity was extreme—requiring a deep understanding of business rules, rounding errors, and multi-party transactions.
  • Behavioral Modeling Complexity: Understanding and simulating customer behavior in uncertain environments required statistical modeling and probabilistic simulations, including Monte Carlo methods.

Solution

We delivered a comprehensive AI-powered system that combined fraud detection, transaction auditing, and behavioral prediction to ensure financial accuracy and security across all customer interactions.

Key System Components

01. Data Pipeline and Storage

Built a custom parsing engine to convert raw JSON logs into structured customer-level transaction data. Data was ingested and stored in MongoDB, providing flexibility for nested data and ease of querying for temporal sequences of actions.

02. Transaction & Payout Audit

Created a deterministic auditing framework to replicate and verify payout and balance calculations. Detected bugs and logic flaws in the live system, particularly in edge scenarios like rounding errors, simultaneous disconnections, and new financial products not covered by legacy logic.

03. Customer Behavior Prediction

Trained customer classification and fraud detection models based on historical activity, transaction features, and action sequences. Used LightGBM for fast gradient boosting classification and PyTorch for custom behavioral modeling components.

04. Monte Carlo Simulations

Employed Monte Carlo simulations to estimate lifetime value distributions and transaction likelihoods under uncertainty. The model was tracked and iterated using Weights & Biases for experiment tracking and hyperparameter tuning.

Design Decisions

  • MongoDB was chosen over traditional RDBMS to handle the semi-structured nature of transaction logs and flexibility in schema evolution.
  • LightGBM provided a performant, interpretable baseline model—essential for understanding fraud-like behavior before deeper neural architectures were introduced.
  • PyTorch allowed greater flexibility for modeling sequences and experimenting with temporal embeddings.
  • Using W&B enabled transparent experiment tracking and model comparisons over dozens of iterations.

If you're looking for scalable SaaS design, deep integration with complex APIs, or predictive tooling for real-world operations—this project is a proven case study of robust, end-to-end execution.

Project Info

  • Role: ML Engineer
  • Type: Financial ML & Audit System
  • Date: 2023
  • Domain: Financial Services

Tech Stack

  • Data Storage: MongoDB
  • ML Models: LightGBM, PyTorch
  • Simulation: Monte Carlo (Custom)
  • Processing: Custom Python Pipeline
  • Tracking: Weights & Biases