Swish allows to send using an arbitrary number (phone or arbitrarily assigned) rather than an actual account number.
It's also credits the recipient immediately. That's possible since all the participating banks have deposited a number of billions in a mutual fund designed to cover the losses in the case one of the banks runs out of money, and also probably by having an internal account to debit during the day.
They are tranfering money between the banks at one (or maybe a few) standard clearing runs involving the Riksbank, that works more or less like ACH. I think all of them are scheduled in the morning.
All Swedish banks are working onreplacing the payment infrastructure (the clearing. ) It's supposed to be finished in 2024 or something like that.
