Real-Time Fraud Detection & Prevention

Nitish John Toppo
Dec 01 2025|10 min read

Problem Statement
Financial institutions and digital platforms face growing challenges with fraudulent activities, such as unauthorized transactions, identity theft, and account takeovers. Traditional rule-based systems are slow to adapt and often lead to high false positives, frustrating genuine users and leaving gaps for sophisticated fraudsters. A predictive AI-driven system is required to detect fraud in real-time, prevent losses, and ensure customer trust.
Project Objectives
- Build a real-time fraud detection system capable of analyzing transactions instantly.
- Reduce false positives while maximizing fraud detection accuracy.
- Leverage both vendor-provided external data (e.g., device intelligence, IP reputation) and internal historical fraud patterns.
- Continuously evaluate and improve fraud detection models to stay ahead of new fraud tactics.
- Provide actionable reports and dashboards for fraud prevention teams.
Scope of Work
Data Ingestion:
- Collect real-time transaction streams and metadata.
- Use vendor data for new or unverified users (e.g., geolocation, IP risk score).
- Use internal data (historical fraud, transaction history, device patterns) for existing users.
Data Preprocessing:
- Clean and normalize transaction logs.
- Identify key data points (e.g., transaction amount, velocity, geolocation, device ID, merchant category).
Model Development:
- Train predictive models (Random Forest, LightGBM, XGBoost) to classify transactions as fraudulent or legitimate.
- Apply hyper parameter tuning to minimize false positives while improving fraud detection.
Validation & Evaluation:
- Validate models against historical fraud cases.
- Compare results across models using metrics like AUC, precision, recall, and F1-score.
- Select the model offering the best trade-off between fraud detection and customer experience.
Deployment & Monitoring:
- Deploy models on Databricks with streaming support for real-time inference.
- Generate alerts and risk scores instantly for suspicious transactions.
- Re-evaluate models periodically using new fraud patterns.
Approach Followed
Data Collection & Integration
- Vendor data used for new/unverified transactions.
- Internal fraud detection history leveraged for supervised model training.
- Transactional and behavioral data stored in MySQL.
Data Cleaning & Feature Engineering
- Removed noise from transaction logs and standardized data formats.
- Engineered features such as transaction velocity, unusual geolocation, device fingerprint mismatches, and time-of-day anomalies.
Model Training & Validation
- Implemented Random Forest, LightGBM, and XGBoost models using PySpark on Databricks.
- Performed hyperparameter tuning to maximize fraud detection accuracy.
- Validated on past fraud cases to check generalizability.
Performance Evaluation
- Models compared using AUC, recall (fraud detection rate), precision (to reduce false alarms), and latency (real-time suitability).
- Chose the model providing the best balance between fraud prevention and customer experience.
Reporting & Continuous Monitoring
- Generated fraud detection reports highlighting transaction risk levels.
- Set up automated re-training and evaluation cycles to adapt to evolving fraud patterns.
Tech Stack
- Data Storage: MySQL
- Data Processing: PySpark, Databricks
- Programming Language: Python
- Machine Learning Models: Random Forest, LightGBM, XGBoost
- Model Optimization: Hyperparameter Tuning
- Deployment & Monitoring: Databricks Streaming, Real-Time Dashboards
Blogs you may like
There are no more blogs for this category