Switch from card to bank halfway through our checkout and the total changes while you're looking at it.
That's not a glitch. And your browser didn't do the maths.
Here's why the number moves.
The two payment rails don't cost the same. A card runs roughly 2.9% plus 30 cents. A bank transfer runs roughly 0.8%, capped at $5.
On a $400 disclosure package that's about $11.90 versus about $3.20.
If a checkout hides that gap, somebody is quietly eating it. Usually the management company. On every order. Forever.
So we show it. Itemised, added on top, labelled, and recalculated the instant you switch rails.
Now the important part, and it's the least glamorous sentence I'll write this month:
The recalculation does not happen in the browser.Your browser is the customer's side of the counter. Anything drawn there can be re-drawn by anyone with ten minutes and mild curiosity. Including a total.
So when you switch to bank, the page doesn't work out a new price. It just reports that you switched. The server rebuilds the entire total from the payment record it opened the order with — a sealed stub the payment processor holds, that nobody on the customer's side can reach or edit.
The browser may ask the question. It never gets to answer it.Three smaller things that took embarrassingly long to get right:
→ It waits until you're signed in before it takes money, so the order has somewhere to live afterwards.
→ It asks for a shipping address only if you picked a delivery option that physically needs one.
→ Who absorbs the card processing fee is a per-company policy, not a hard-coded assumption. The company absorbs it, we absorb it out of our own cut, or the buyer covers it on a grossed-up charge so the company still nets the full price.
That dial is a whole post of its own, much later in this series.
For today: prices that change honestly, worked out somewhere the customer can't reach.
Next: the screen that answers "where's my package?" before anyone types it.