Engineering notes from the trenches of building software.
Practical, no-hype writing for developers and businesses - on AI, ERPNext, Frappe, Linux and shipping software. I cut through the noise to what actually works, with a sharp eye on what it all means for Africa.
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Don't Get Pressured Into Buying AI Before Your Business Is Ready
The hype says buy AI now or be left behind. The truth is most businesses aren't ready yet, and rushing wastes money, frustrates teams and quietly breaks customer trust. Using the Ngazi ladder, here's how to find the rung you're really on and take the one step that pays off.
Recent articles
One tap at the till, five documents: the submit chain behind ERPNext retail
I recorded an hour and twenty minutes of UpeoRetail and refused to cut the boring parts, because the eight seconds at the counter is the easy bit. What one submit really writes: stock ledger, GL, a serial and batch bundle, a payment, and two integrations that live outside the transaction.
Your spare Android phone is a payment gateway: an offline-first SMS relay for M-Pesa
M-Pesa till confirmations arrive as an SMS, and Daraja is not open to every merchant. So we turned a spare Android phone into a self-hosted SMS-to-HTTP gateway: encrypted on-device, HMAC-signed on the wire, and built so that it never loses a message.
Metering, model routing and the regression suite that stops your agent rotting
Two questions decide whether an AI feature survives its first year: does each request make money, and will a prompt edit break something silently? An append-only credit ledger, two-tier routing, and a suite that asserts question-to-metric mappings are the answers.
Six ways Android will eat your background service, and what actually worked
A broadcast receiver is a lie, WAL journalling wedged openDatabase on OxygenOS, and one polite database close in a WorkManager teardown silently stopped the whole gateway. Six real failure modes from a production Android SMS gateway, and the fix for each.
Exactly-once over an unreliable pipe: HMAC, nonces, and a byte-exact contract
A per-request nonce and a per-content hash look like the same idea and are not. One says this request arrived twice, the other says this message arrived twice, and a payment pipeline needs both. The signing design behind a production SMS gateway.
Shipping an Android app that can never be on the Play Store
Play forbids READ_SMS for anything that is not the default SMS handler, so this app was never going to be listed. Then a silent fallback to the debug keystore and a versionCode stuck at 1 turned every update into an uninstall. Two traps, one incident.