Unified Payments Interface (UPI) is an instant payment
system developed by the National Payments Corporation of India (NPCI), an RBI
regulated entity. UPI is built over the IMPS infrastructure and allows you to
instantly transfer money between any two parties' bank accounts.
A Virtual
Payment Address (VPA) is a unique identifier which you can use to send and
receive money on UPI. Think of it as an email ID which you can use to transfer
money.