I’m fairly certain that’s a POS issue, not the payment network.

I’ve heard anecdotally that it’s < 140 ms for payment networks.

Anyone, please correct me if you know better.

It's definitely not 140ms round-trip. Issuer processors typically have a ~2.5s window for approval.

In practice, the POS sends a message to the acquirer processor -> hits the network -> is sent to the issuer processor, and back again.

https://medium.com/wharton-fintech/the-anatomy-of-the-swipe-...

	▲	Spiff1985 3 days ago \| parent [-]
		yeah, if the card is an EMV chip card, and might also have a SVA so everything is handled between the terminal and card, it can be blazingly fast. In EU they use of offline PIN was used massively before PSD2 and contactless, that made the terminal request during the time it took for validating the transaction online, and basically as soon as the PIN was ok'ed by the card that confirmed the transaction. That gave a perception of speed. Now it's basically online PIN mostly or contactless, but that means you perceive a "wait for an ok", that you had before but was masked by the PIN capture and check on device/card. So we went a bit backwards for cards, but wallets like ApplePay went a bit forward. You win some you lose some I guess

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felipellrocha 4 days ago | parent | prev [-]

140ms is still a ton of time to do a simple transaction

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ivlozada 4 days ago | parent [-]

It's not simple though. In that 140ms the network is checking fraud rules, validating the card, checking available credit, applying rewards logic, and routing across multiple parties. The actual subtract-one-number-from-another takes microseconds. The rest is trust verification across organizational boundaries — which is the hard part of any payment system.

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mattclarkdotnet 3 days ago | parent [-]

At best it’s checking available credit. All the other stuff is done after the fact. The idea that any banking transaction involves “subtracting one number from another” is so wrong it’s barely worth engaging with.

	▲	dcrazy 3 days ago \| parent \| next [-]
		You speak so confidently, yet it appears you’ve never gotten a text asking you to approve or deny a charge that you are performing.
	▲	skywhopper 3 days ago \| parent \| prev [-]
		Some (rewards processing) is probably done later, but the fraud check definitely isn’t.