Generator Tracker is a logbook for power generators. Scheduled blackouts in Ukraine turned generators into everyday appliances — and engine hours, oil changes and fuel are easy to lose track of, especially since most portable generators have no hour meter.

• One tap to Start/Stop: engine hours count themselves; several generators can run at once; Undo a mistaken Stop

• Fuel left and runtime estimate from the tank size; litres or US gallons per hour from your refills (switch in Settings)

• Maintenance by engine hours, days or both — overdue tasks show on the home screen

• Monthly charts of hours and fuel per generator

• Big buttons for the dark and a true black theme that saves battery during outages

• Offline-first: data stays on the phone; an optional account only syncs your own devices

Under the hood: offline-first sync with pending state instead of a queue, tombstones for deletes and a pure last-write-wins merge, covered by unit and emulator tests. Native SwiftUI forms on iOS, Material 3 on Android. Open source (MIT).

iPhone: free (ads on two screens, removable with a one-time purchase) + public TestFlight beta: testflight.apple.com/join/wZcGdJar. Android: full paid app without ads (Google Play), and a free Lite version in closed testing — testers welcome: groups.google.com/g/generator-tracker-lite