Engineering notes
Four decisions from building a business platform single-handed, written for somebody who will never see the code. Each one is a thing that turned out to be wrong, what it cost to find out, and the rule that outlived it.
These come from one project: a multi-tenant business platform for professional firms, where the customers, the projects, the hours, the quotes and the invoices are joined end to end instead of sold as five tools that happen to share a login. Around it sit the public sites, the documentation and the developer tooling it is built with — seven deployed applications and one Postgres database, in a single repository.
It is built and run by one person, outside the hours of a full-time job. That is context rather than a boast, and it is the reason the notes read the way they do: alone, you cannot out-work a mistake, so what matters is leverage — what to automate, what to refuse to claim, and which checks earn back more than the time they cost.
The code is private and none of it is given away here. What these describe is method: how something was measured, what the measurement contradicted, and what changed as a result. A method is worth more read than hoarded — and it is the part nobody can copy without first understanding it.
GA has to be earned
A maturity label whose default is "not proven", and a tool that refuses to promote more often than it promotes.
Written August 2026
A green check that never looked
The probe reported "ok, 7 React fibres". It was measuring the framework’s own 500 page, which is React, and hydrates.
Written August 2026
One boolean answering two questions
A flag meant both "this data is disposable" and "do not touch the outside world". The one workspace that needed opposite answers is where it broke.
Written August 2026
Three failing tests, and two copies of the runner
Out of 2 743 tests, three failed on snapshots and nothing else did. The cause was a package manager resolving one dependency twice.
Written August 2026