Recent advances in Unified payment interfaces (UPI) has quickly changed the way of conducting digital transactions which allows the users and service providers to make real time, easy transactions around various platforms have increased the need for system to balance speed, secured and scalable digital transactions. However, existing approaches suffer from several key challenges including limited environment, scalability issues, security and privacy remains as persistent issues and performance measures like speed, reliability and energy efficiency are frequently neglected. This paper proposes UPI environment by showing the transaction flow, how users and service providers interact with each other and how authentication works. It highlights the gap in performance, security, scalability, user awareness and creating a foundation for more robust, user friendly digital payment system to address the pointed limitations. the proposed approach utilizes UPI transaction workflows, authentication mechanism, entity interactions including users, banks, payment service providers and is implemented using Hyperledger fabric for network blockchain with docker and docker compose for service encapsulation and coordination. UPI transaction flow is developed using Go/Node.js chaincode, while performance metrics are measured using Hyperledger Caliper, all within stable ubuntu environment. Experimental evaluation demonstrate that the proposed system achieves real-world baseline model for transactions, monitoring both performance metrics including transaction throughput, latency, fault tolerance and user behaviors like transaction patterns, authentication practices and fraud awareness. Compared to existing approaches, our system provides more practical view of performance by noticing faster transaction processing, lower latency, and strong blockchain design along with understanding into user behavior and fraud awareness. These results indicates that our system offers more scalable, secure and robust framework for analysis and future improvements.