Your phone knows where it is without internet: GPS is satellites, not data. What needs a connection is telling anyone else. So in a dead zone, a well-built tracker keeps recording your position on the phone and sends the whole route the moment a signal returns; a poorly built one simply loses that stretch. Which kind you have shows up the first time you drive through a tunnel or a village with no signal.

What Traxl does with mobile data off

  • Every position fix is written to a queue on the phone before any attempt to send it, so a dropped connection never loses a point.
  • The queue holds about a week of fixes. Older ones are dropped first if it ever fills.
  • The instant the phone sees a network again, even for a few seconds, the queue uploads in batches. The app also uploads when opened, and a background job the OS runs independently uploads even if the app was killed.
  • Your own History shows the route from the phone’s queue straight away, marked as still uploading, so you can check a trip recorded before it has reached anyone else.
  • The server keeps each fix at its original time, so the route appears in the right place on the day, not bunched at the moment the upload happened.

What your Circle sees in the meantime

Your dot freezes at your last sent position with an “updated 25m ago” label. Nothing is invented. When the upload lands, the route fills in and the dot jumps to where you are now.

What doesn’t work offline, honestly

  • Place alerts for you are late: they fire when your fixes arrive, not when you crossed the boundary.
  • SOS can’t be sent. The app tells you it didn’t go out rather than pretending.
  • The map background needs data. The route line, pins and stats still draw over a grey map.

A phone with the wrong time

One subtle failure we fixed: a phone whose clock runs a few minutes fast stamps its offline fixes in the future, and a strict server would reject them all. Traxl now detects that and shifts the batch back by the clock error. Keeping “Set time automatically” on in Android settings avoids the question entirely.