Short write‑ups of problems we hit running a real commerce operation and what we changed in the code because of them. No product announcements; just the reasoning.
The factory counts in units, the shop counts in boxes, and no amount of wishing makes 16 divide by 10. Rather than force one side to surrender, we named the exchange rate, converted at exactly two edges, and taught the system to say "one sealed box and six loose" out loud. Then we let small orders wait at the roadside until something bigger came past going the same way.