A working model · two seconds, at real speed
Followthe money
You tap, you swipe, or you insert the card.This is everything that happens next, live.
Three people live inside every card payment: the one who taps, the shop that accepts, and the people who build the rails between them. This page works from any of those seats. Everything below is playable, so tap what invites tapping, and carry one question through all four acts: where is the money right now, and who is on the hook if this step fails?
First, choose this tap's fate
Then tap the card
02 · The economics
The tap is free. The system is not.
So who pays for the two seconds? Not you, at least not directly. The merchant receives slightly less than you paid, and the difference is divided among everyone who carried the question: the issuer's share is called interchange, the network takes its fee, the acquirer keeps a margin. Drag the amount and watch the split — this small arithmetic is the business model of every card on earth.
- Interchange · to the issuer
- $1.70
- Network fee · to the scheme
- $0.15
- Acquirer margin
- $0.45
- The merchant keeps
- $97.70
- If you carry the card
- Your rewards are not a gift. Points and cash-back are paid out of interchange, which means the shop just funded your miles. It is also why the corner store sets a card minimum: on a small ticket, the fixed part of the fee eats the margin.
- If you run the shop
- This split is what card acceptance actually costs you, and most of it is set by the networks and not up for discussion. The acquirer margin is the one line you can shop around on. That is what you are really comparing when you compare processors.
- If you build the rails
- Interchange is the gravity of the whole system. It funds card programs, decides which products issuers push, and explains why every fintech eventually wants to issue a card. Follow it and most strategy in this industry starts to make sense.
03 · That night, and the next day
No money moved when you paid.
If the approval took two seconds, when does the shop actually get the money? Here is the part almost nobody knows: at the moment of approval, not one naira or cent has moved. The approval was a promise, the issuer saying I am good for this, hold my word. The money keeps that promise overnight — press play and watch eighteen hours in ten seconds.
5:03 PM
04 · When it goes wrong
The argument after the money moved.
Disputes are the part of payments people feel the most and understand the least, and they are not one thing. A stolen card, an order that never came, a subscription you cancelled twice, a charge that only looks doubled: same rail, four different arguments. So this act is a case file rather than a diagram. Pick one, and it plays out a filing at a time. You will make the calls.
I have spent ten years building the systems in this story, on the issuing side and the acquiring side, in Lagos and Toronto. The two seconds are my day job.
If you want the longer version, the work is here.
Further reading: The Anatomy of the Swipe, Ahmed Siddiqui — the book that maps this territory in full.