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Migrating the American express payment network, twice

americanexpress.io

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Re: Migrating the American express payment network, twice

#21

Post by inkyoto »

mattclarkdotnet wrote: post #6
alberth wrote: post #4

Re: transition to micro services (from monolith). I’m surprised a network so sensitive to latency (as are payment networks), was able to achieve their latency SLAs with micro services. Maybe Amex being a closed-loop network helps with latency?

Since when were payment networks latency sensitive? It’s usually 2 or more seconds to even get a payment up on the card terminal from the merchant POST system, then 2-5 seconds more from card presentation to getting approval back.

> Since when were payment networks latency sensitive?

Since the advent of e-commerce, POS-networking and fraud detection systems in 1990's-2000's.

User-facing and authorisation path are highly latency sensitive. It includes tap-to-pay, online checkout, issuer authorisation, fraud decisioning, and instant payment confirmation – even moreso for EFT payments.

> […] 2-5 seconds more from card presentation to getting approval back.

This is the mid-1990's level QoS when smaller merchants connected the acquirer bank via a modem connection, and larger ones via ISDN.

Today, payments are nearly instant in most cases, with longer than one-second card payment flows falling into the exceptions territory or inadequate condition of the payment infrastructure.

Re: Migrating the American express payment network, twice

#23

Post by bob1029 »

alberth wrote: post #4

Re: transition to micro services (from monolith). I’m surprised a network so sensitive to latency (as are payment networks), was able to achieve their latency SLAs with micro services. Maybe Amex being a closed-loop network helps with latency?

> Maybe Amex being a closed-loop network helps with latency?

Yes, this is a huge deal. VisaNet and friends have to wait on the actual bank cores in order to perform online authorization. Amex can guarantee end to end latency.

Re: Migrating the American express payment network, twice

#24

Post by usrnm »

skrtskrt wrote: post #17
alberth wrote: post #4

Re: transition to micro services (from monolith). I’m surprised a network so sensitive to latency (as are payment networks), was able to achieve their latency SLAs with micro services. Maybe Amex being a closed-loop network helps with latency?

Every major high-throughput database now runs as microservices, not sure why people still act like things just grind to a halt when the network is involved.

High-throughput is not the same thing as low latency. In fact, they're often at odds with each other

Re: Migrating the American express payment network, twice

#25

Post by compounding_it »

mattclarkdotnet wrote: post #6
alberth wrote: post #4

Re: transition to micro services (from monolith). I’m surprised a network so sensitive to latency (as are payment networks), was able to achieve their latency SLAs with micro services. Maybe Amex being a closed-loop network helps with latency?

Since when were payment networks latency sensitive? It’s usually 2 or more seconds to even get a payment up on the card terminal from the merchant POST system, then 2-5 seconds more from card presentation to getting approval back.

>Since when were payment networks latency sensitive?

Apple Pay is extremely fast from my experience (at least the web version). There is a high percentage of market loss if payments take long or fail. Im sure there must be a graph for where it plateaus with diminishing returns when it comes to speed but faster payments definitely help with sales.

Re: Migrating the American express payment network, twice

#26

Post by mattclarkdotnet »

ivlozada wrote: post #16
felipellrocha wrote: post #13

Earlier quoted context omitted.

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

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.

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.

Re: Migrating the American express payment network, twice

#28

Post by jamiemallers »

themafia wrote: post #2

This is cool, but a part of me has to be flip, and humanity is kind of hilarious to me. All of this amazing infrastructure and hard work to essentially just very carefully and accurately subtract one number from another in a way that makes auditing easy.

[dead]

Re: Migrating the American express payment network, twice

#29

Post by skywhopper »

mattclarkdotnet wrote: post #26
ivlozada wrote: post #16

Earlier quoted context omitted.

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.

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.

Some (rewards processing) is probably done later, but the fraud check definitely isn’t.
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