[ErrantX]

They use largely the same rails/network (for example Mastercard). The only meaningful difference is on how and when funds are reconciled.

Some payment providers ask up front to simplify the flows as it's not totally trivial to determine what sort of card it is, and also because different fees apply - historically some merchants added specific fees to basket etc. (less so nowadays but the UI convention sticks)

[cesarb]

> Some payment providers ask up front to simplify the flows as it's not totally trivial to determine what sort of card it is

And because the same card can be both. At least here in Brazil, most bank cards have multiple uses (credit, debit, ATM) in the same card. AFAIK, they're separate applications within the same chip, and the terminal has to select which one to use before starting.

[ErrantX]

Interesting! Did not know that offhand but just looked it up in the technical docs and this is part of the standard. Interesting to hear how other countries have adopted different approaches.

[quacksilver]

From memory, online and offline transactions are usually split out by BIN number (first six digits)

The BIN will tell you which bank was the issuer and which class of card you have, like standard or premium, though most readers probably don't take that into account beyond the card scheme and card type associated with the range that the individual BIN is in. Many banks will have multiple BINs for the same card type if they are large.

Credit / online debit / offline debit usually get different ranges. The reader gets a list of the ranges when it updates and they don't change super often. Offline readers can be configured to reject cards with a number in an online only range.

[lxgr]

It's usually based on the chip settings. Rules aren't as simple as "always online" or "never offline"; an issuer can e.g. convey that they'd prefer online transactions for certain types of payments, while offline is ok for others, via relatively complex configurations of the code of the chip application.

Before that, there was the service code on the magnetic stripe, which also can convey things like "online only" or "domestic use only".

The BIN is only involved in risk management on the terminal's side: Many of these in-flight terminal accept deferred online transactions, which means that, even though they're completely offline, they take the risk of accepting an online-only card. (For truly offline capable cards, the risk is often with the issuing bank.)

That type of risk management can benefit from knowing what type of card it is, and prepaid cards are often seen as riskier (because customers might intentionally drain them before a flight). Of course, debit and credit cards can also be empty/marked as stolen, but these are marginally harder to get and replace.

[avianlyric]

> The only meaningful difference is on how and when funds are reconciled.

Nope, even this is identical. These days the difference between a debit/credit card is pretty much aesthetic, from a transaction processing perspective there generally isn’t any actual differences. Differences that people see today are most artificial for the purpose of justifying extra fees, or higher interchange based an entirely arbitrary factor that has zero correlation to any risks that appear in the transaction processing and clearing mechanisms.

Basically the only reason anyone really bothers keeping the difference between credit/debit cards around, is as a technical excuse for discrimination and abusive fees. Notably in the EU nobody cares if a debit or credit card is used, because the EU outlawed all the crazy fees and other bullshit, so now there’s no commercial reason to differentiate between the two 99% of the time.

[ErrantX]

There are a few differences for sure. All entirely technical in how the money moves or clears. The most obvious point here is debit card moves your money from your account, credit moves the issuers money from their account.

But to your wider point; from a transaction fee point of view you are dead right. Of course a credit card has other attractions; for example it's credit :D but also things like section 75 protection.