Offline-first data collection for field ecologists

The challenge

Researchers recorded species counts on paper because the previous app lost data when it went offline mid-survey.

Surveys change every season, and each change used to need a developer and a new app release.

The approach

• Audited the old app and wrote up why it lost data before proposing a rebuild.
• Stored every survey locally in SQLite and synced with a simple, append-only change log instead of last-write-wins.
• Defined survey forms as versioned JSON schemas so the research team can add questions without a release.
• Tested sync on throttled and flaky networks in CI, not just on the office Wi-Fi.

The result

The team ran a full season of field work on the new app. Survey types are now edited by the researchers themselves and reviewed in a pull request.