The places you count are the places phones lose signal. Walk-in coolers are metal boxes. Basements are under a building. A warehouse is steel racking in a concrete shell. It is not a coincidence — it is the same physics every time — and it is why an inventory app that only works online is an inventory app that works everywhere except where the stock is.
The device is the source of truth first
When you scan an item and type a quantity, that number is written to your phone before anything else happens. Not attempted against a server, not held in memory hoping for a connection — written down. From the app's point of view the count is already complete and saved; sending it somewhere is a separate, later problem.
That inversion is the whole design. It means a dead zone is not an error state. There is no banner telling you to try again later, because there is nothing to try again.
What works with no connection
- Counting — storage, category and mixed counts, start to finalise.
- Adding and editing products, including creating one from a barcode you have never scanned before.
- Picking against a list, and receiving a delivery.
- Tasks: creating them, completing them, reassigning them.
What needs a connection
- The first sign-in on a device. After that, Face ID or a fingerprint works offline.
- Syncing, obviously — that is the part that needs the network by definition.
- Photo uploads. The photo is taken and kept locally; the upload waits.
- Live views that are computed server-side, such as the low-stock card and parts of the dashboard.
Why the queue is ordered
This is the part that is easy to underestimate. Work done offline is kept in the sequence you did it, and replayed in that sequence when the connection returns. If you received twenty units at 10:04 and picked six of them at 10:20, the history shows a receipt and then a pick — not both arriving together with an ambiguous order.
It matters because the activity history on a product is what you use to answer questions later. "Where did these eight go?" is answerable when the events are in order and unanswerable when they are a bag of facts with the same timestamp.
There is no sync button
trakr watches for a connection and sends the queue itself. There is nothing to remember, which is the point — the person doing the counting should not also be responsible for the plumbing. Walk out of the walk-in, and by the time you are back at the pass it has gone.
What this means in practice
Plan counts around the room rather than around the reception. Split the walk-in and the dry store between two people even though neither has signal. Let someone finish a count in a basement on a phone that has been in aeroplane mode the whole time. None of it is a special case, and none of it needs anybody to think about it.