This option is not available in all countries, but you can check with your bank and use the option whenever possible. UPI stands for Unified Payment Interface; it is a digital payment method which does not require the use of a credit or debit card to make a transaction. You need to download the UPI app to your mobile; this can be provided by your bank, if not download a third party UPI app via Google, PayTM etc. If your bank does not provide you with the UPI and you go for a third party UPI your mobile number serves as your virtual private address (VPA). When making a payment using VPA, you get a message indicating the payment to be made, and only once you tap on the transfer funds button will the money go through. Do check with your bank or online for more details on using UPI for online purchases. Similarly, Sri Lanka offers eZ Cash, etc.