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Fed’s new instant payment system could be trouble for PayPal, Venmo
(arstechnica.com)
This is a most excellent place for technology news and articles.
In Australia we've had free next business day transfers for as long as I can remember. Decades.
The transition to transfers that clear in seconds was happened gradually as bottlenecks were removed from the infrastructure one by one. Some transactions were instant a couple decades ago, but it's only in the last few years that most transactions are instant here.
These days, Visa/Mastercard are basically the slowest way you can pay someone. It's still the most commonly used option though, since it has the best fraud protection.