[akiselev]

Last time I worked with (on?) a payment processor we got special credit cards that worked like Stripe's test numbers for testing production. I.e. some cards would go through, others would fail with errors specific to each card number.

They were probably one of the most closely guarded pieces of equipment we had since the cards that cleared did so at any merchant so it'd work at point of sale but the vendor would never receive the money.

[zacmps]

I'm surprised the payment system is designed in such a way to make that possible

[akiselev]

It's the way the credit system was designed, even before widespread computer networking - based entirely on trust. The customer would bring the card in and the merchant would make a signed carbon copy and call it in or deliver the receipts to the bank every day, which would settle the accounts between banks over a week or so, with the credit card provider carrying some level of liability. This is one of the reasons credit cards weren't accepted most places until networked POS terminals and instantaneous verification made the trust more practical.

Some merchants have their own verification steps in addition to the terminal like Best Buy checking a customer's ID to see if it matches the card and one of these special cards wouldn't fly if anyone actually looked it. It's not like you can walk into a Lamborghini dealership with one like you can with a Centurion card (which has some sort of concierge service for verifying large purchases IIRC).

[derefr]

Presumably, somewhere within the bowels of American Express, there's a test card for testing the Centurion large-payment verification process, where feeding it through a merchant and having them run a verification on it, will get them routed to a mock concierge on Amex's side (or rather, a human concierge diverted to follow a special mock workflow script.)

[arthurcolle]

"Everytime you run your test suite, someone actually gets up for every test case, runs over to the copy machine, and creates physical carbon copies for DHS."

[adav]

They should have mock Lamborghini dealerships and mock supercar test-drives so any developers debugging can be confident of all their changes.

[koolba]

It’s really easy to set this up. Authorizations for changes get routed to the bank of the issuer. It’s no different than rejecting for a bad a zip code, except it’s based purely off the card number.