Offline-first in React Native: an app with no backend

I built Protokolka, an app for flat handover reports, without a server. No sign-up, no synchronisation, no personal data processed on my side. So far I consider it the best decision of the project — and at the same time the source of problems I had not read about anywhere beforehand.

The reason was originally purely practical. A handover report contains photos of the flat, the names of both parties and their signatures. The moment that travels to my server, I become a processor of personal data with everything that entails.

Why offline-first is recommended

• Zero running costs — the app pays for itself.
• It works in a basement with no signal, which is exactly where handovers happen.
• No account means two fewer screens in onboarding.

Where the data actually sits

Metadata in a local database, photos in the file system, generated PDFs in a shared folder. This is where I hit something no general piece of advice warned me about firmly enough: do not store absolute paths. On iOS the app container changes after an update and stored references to photos fall apart.

Store relative paths and assemble absolute ones only when reading. I learned this after the first report of "my photos have disappeared".

Backups are a feature, not a settings detail

With no server, losing the phone means losing the data. The recommendation — and it makes sense to me — is to have export-everything-to-one-file visible in the main part of the app, not buried three levels deep in settings. The user has to know that backing up is on them.

When to add a backend

The line I hold to: the moment data needs to be shared by more people or more devices. Until then a server is mostly cost and risk. Whether I will cross that line with this app one day, I do not know yet.

This is not a prescription for every app — for plenty of products a server is a necessity from day one. Take it as a description of one scenario where it was worth putting off as long as possible.