Unified Payments Interface (UPI) is a payment system launched by National Payments Corporation of India (regulated by RBI). It is to facilitate instant fund transfer between two bank accounts without sharing account details or adding a beneficiary, as is the case with options like IMPS transfer.
Apart from releasing its own mobile application, the BHIM app, NPCI has collaborated with many banks in India to provide UPI services to customers at large. In such collaborations, banks use BHIM platform on their mobile banking applications to provide UPI-based inter-bank fund transfers.