1Shaik Siddhik, 2Shaik Mohith, 3Gunja Sirisha, 4Yadagiri Vasantha Laxmi, 5Mr.N. Anjaneyulu 03 04 The rapid growth of online payment systems has significantly increased the risk of financial fraud Fraudulent transactions cause substantial financial losses to individuals banks and ecommerce platforms A major challenge in fraud detection is the highly imbalanced nature of transaction datasets where fraudulent cases are rare compared to legitimate ones Traditional machine learning models tend to be biased toward majority classes resulting in poor fraud detection rates This project proposes an Online Fraud Payment Detection system using balanced machine learning algorithms to address class imbalance Data balancing techniques such as SMOTE and undersampling are applied to improve model performance Multiple machine learning classifiers are trained and evaluated on balanced datasets Features related to transaction amount location time and user behavior are analyzed The system accurately identifies fraudulent transactions in real time Performance is evaluated using precision recall F1score and ROCAUC metrics The model minimizes false negatives which are critical in fraud detection Automated alerts notify stakeholders of suspicious activities The system improves decisionmaking for financial institutions Scalability ensures handling of highvolume transactions Security and data privacy are maintained throughout the process The proposed approach enhances fraud detection accuracy and reliability Overall the system provides a robust and efficient solution for online payment fraud prevention Copyright (c) Journal of Science Engineering Technology and Management Science. All rights reserved 2026