[someonenice]

There is India's UPI (launched in 2016), Singapore PayNow (Launched 2017) that works in a similar way. And they also work across each platform.. UPI users in India can transfer to Paynow users in Singapore and vice versa.

[1] https://www.dbs.com.sg/personal/deposits/pay-with-ease/payno...

[gmerc]

Thailand Promptpay is federated too, as are some Japanese services.

[lmz]

some UPI users to some Paynow users. (limited to participating institutions only).