Comment by toomuchtodo

19 hours ago

Central bank instant payment system. The US has FedNow, and has had it for almost 3 years. It costs a few pennies to move up to $10M per XML message.

Brazil's Pix costs ~$10M/year to run: https://www.pymnts.com/wp-content/uploads/2026/09/PYMNTS-Int... [pdf] (September 2026 revision)

FedNow is a payments rail, which is a long shot away from being a full retail payments scheme. The latter needs a disputes story, customer knowledge, merchant acceptance…

Take SEPA Instant, for example. It’s great for many things, but effectively nobody pays using it in stores or even online.

> Walmart is currently trialing it to save $3B-$7B a year in interchange fees. No crypto, just XML messages through a mainframe at the Federal Reserve with a 20 second SLA.

Please tell your user that this SLA is much too high for many purposes. A cafe or such would lose a ton of money if every transaction took 20 seconds longer to conduct.

  • It's the worst case before they get penalized. I've had worse times with Mastercard and Visa. It's really not a big deal if one in a thousand payments, you sit by the card reader for 30 seconds before it says "please try again".

  • Works fine based on the evidence. It’s a maximum SLA, not every transaction. The economics are too compelling to ignore. Fast enough.