[miki123211]

> Unlike Visa and Mastercard, I noticed that AMEX transaction notifications are near-instantaneous.

No idea where you bank, but my Visa notifications are instantaneous, so the network is clearly capable of that. I'm with a modern European bank though, I wouldn't be surprised if the mainframe-lowing US banks that do everything via overnight batch jobs are incapable of this.

With that said, there are places which straight up won't send your transaction to the network at purchasing time. Apple[1] is one notable example. They seem to have a cron job that runs at midnight and does billing for that day. This is really annoying if you're buying an expensive Apple product and increase your card limits for one day only.

I've even seen places that do extremely-low-value transactions "on faith" - the transaction is entirely offline, it gets send to the network the next day, and if it is rejected, your card number goes on a blacklist until you visit the company's office in person and settle the debt.

[nulbyte]

> I'm with a modern European bank though, I wouldn't be surprised if the mainframe-lowing US banks that do everything via overnight batch jobs are incapable of this.

I wouldn't be surprised if your European bank still relies quite heavily on its mainframes. The mainframe offers high availability, reliability, and, contrary to popular belief, high throughput. Batch processing is just one thing they're good at; real-time processing at high speed is another.

[j16sdiz]

You missed the footnote for [1].

Did you meant Apple Card, Apple Pay or the Apple Store?