Writing
Decisions from systems that are running in production, written up from the engineering notes kept while building them. Each one states the constraint, what was chosen, and — where it applies — the bug that forced the rule.
Personal projects only. Work done for employers and clients is deliberately absent; those systems are not mine to describe.
7 min
The quote that must not expire
Klang Ya Bhaesaj
A B2B order flow where approval reserves stock and creates the order in one transaction — and the null check that stops a converted quote from silently giving that stock back.
6 min
Deriving the base unit instead of flagging it
Klang Ya Bhaesaj
Pharmacies buy the same drug by tablet, strip, box and carton. Modelling that with a boolean column looked obvious and was wrong; migration 0040 deleted it.
6 min
Empty scope means everything
Klang Ya Bhaesaj
A promotions engine where an empty scope means all products, not none — plus the per-item clamp that turned a ฿70 discount into ฿220 when it was missing.
5 min
Selling access, not files
English with Gift
Course video that only the right student can reach, for the window they paid for — signed URLs, permissions with an expiry, and an honest account of what this does not stop.