The problem
Maintenance engineers were working from paper job sheets. The sheet went out in the van, got filled in on site, came back at the end of the week — or did not — and was then typed into a spreadsheet by somebody in an office.
Every step of that leaks. Handwriting is ambiguous, sheets get lost, the office is always working from information that is several days old, and the engineer who did the work has moved on to something else by the time anyone queries it.
The obstacle to fixing it was never the office side. It was that engineers work in plant rooms, basements and lift shafts, and any replacement had to keep working where a mobile signal does not.
What I built
An installable, mobile-first progressive web app that engineers add to their phone home screen — no app store, no managed devices, no rollout project.
The design constraints drove everything:
- It has to work on a bad connection or none, and reconcile when the signal comes back
- It has to be usable one-handed, on a phone, with dirty hands — an engineer is not going to fill in a twelve-field form
- It has to produce a record the office can rely on without re-keying it
The office side gets what it never had before: what was done, when, by whom, and what state the job is actually in — while the engineer is still on site rather than at the end of the week.
Where it is now
Live and in daily use. 906 commits between June and August 2026.
Worth being straight about this one: unlike most of the work in this index, it was not a solo build. I was the lead contributor rather than the only one, with around 400 of those commits mine. The parts I owned were the offline behaviour and the data model underneath it — the bits that decide whether an app like this survives contact with a basement.