Understanding a credit card transaction takes two different lenses: who's actually involved, and what actually happens, in what order.
The player view: seven entities
A transaction can touch up to seven parties: the consumer, the merchant, the issuing bank, the acquiring bank, a payment processor, a gateway service, and the card association itself. The consumer contacts an issuing bank and opens a credit card account before ever transacting — everything downstream flows from that relationship, routed through whichever combination of processor and gateway the merchant's acquiring bank supports.
Why accepting a card is harder than accepting cash
- Card acceptance: confirming the acquiring bank actually supports the card type presented
- Card authenticity: verifying a genuine card amid constantly changing designs and updates
- Available funds: no visible balance to check — an authorization is the only way to know
- Cardholder verification: confirming the person holding the card is actually authorized to use it
- Delivery timing: rules governing exactly when a merchant is allowed to request payment relative to delivery
The step view: seven processing stages
Card authentication, authorization, authorization reversal, settlement, credits (refunds), chargebacks, and representment — splitting cleanly into a pre-payment phase and a post-payment phase, each with its own risk profile.
Where payment aggregators fit in
Services like PayPal, Google Checkout, and Amazon Payments simplify this entire chain for a merchant, and open up cross-border markets more easily — usually at a real cost premium over traditional card processing.