UPI has been adopted by eight countries and a few dozen are in progress [1]. Additionally, UPI has started to integrate with other nation's similar system (Singapore's PayNow [2] for instance).

[1] https://www.pib.gov.in/PressReleasePage.aspx?PRID=2224505&re... [2] https://www.nipl.com/how-it-works/frequently-asked-questions...