Engineering blog
Practical writing for senior developers, engineering managers and technical founders — performance, data, SaaS architecture, applied AI, payments and mobile.
Integer-cent maths, largest-remainder ledger allocation, a frozen FX rate per invoice, FEFO batch picking and a unique partial index against double-booking, as built in ClinicPro.
How Inventra keeps stock honest: an append-only movement ledger, conditional $inc guards inside transactions, FEFO/FIFO cost layers, and a test that fires 50 parallel reserves at 10 units.
