How to keep selling through internet and power outages
An internet outage at rush hour does not only stop sales; it stops the queue. A customer who waits five minutes at a frozen till leaves their goods and walks out. And in our markets an outage is not a rare event you plan for once; it is a weekly condition that needs a fixed routine.
This guide arranges what you need in four layers: power, connectivity, software, and the human routine. You buy the first three once; the fourth you train your team on once and it becomes habit. In a company with several branches the same layers repeat in every branch, and what matters is that the routine is the same everywhere.
1 · Power before anything else
The cashier's device should be the last thing in the branch to go dark. A laptop with a healthy battery beats a desktop with no backup unit, because a battery gives you hours, not minutes. If your till is a desktop, a small UPS covering the till, the printer and the router is enough for short outages.
A thermal printer only draws power while printing, so do not leave it off the UPS. A receipt printed during the outage is what proves the sale to the customer.
- A laptop or tablet at the till, with at least two hours of battery
- A UPS covering the printer and router if the till is a desktop
- A car charger or spare power bank in the drawer, tested, not new
2 · Do not make the internet a condition of selling
The second layer is not better internet; it is software that does not need it at the moment of sale. Any system that asks the server for every receipt will stop, whatever your subscription. The question to ask a vendor is simple: if I unplug the network cable now, can I scan a barcode and issue a receipt? If the answer begins with "mostly", the answer is no.
The right software keeps products and prices on the device, saves receipts locally during the outage, and sends them when the network returns without recording them twice. That last condition matters: a retry after a drop in the middle of a sync must not create a duplicate receipt or deduct stock twice.
3 · A cheap backup connection
A data SIM in the cashier's phone, with a personal hotspot, is enough as a second line. You do not need a large plan: syncing after an outage is a few kilobytes per receipt. What matters is that the second line has been tried before you need it, not during the queue.
4 · The routine the cashier follows
Write the routine on a card at the counter. When the "offline" bar appears on screen: keep selling as usual, never re-enter a receipt that was already issued, do not close the program, and tell the manager if the outage lasts more than an hour. When the network returns: wait for the sync-complete message before closing the shift, and review the list of pending operations if there is one.
The most common mistake is a well-meaning cashier re-entering a receipt in the belief it was not saved. Good software prevents the duplicate technically, but a written routine prevents the worry in the first place.
In a company with several branches, put the same card on every counter and make each branch manager responsible for reviewing the saved operations after an outage. When every device syncs its own queue, an outage in one branch does not stop the others.
5 · Rehearse the outage before it happens
Once a month, deliberately disconnect the internet for ten minutes at a quiet time. Sell three receipts, reconnect, and confirm that all three appear in the report exactly once. Ten minutes a month buys you certainty at rush hour.
Cashier software that keeps selling when the internet or the power goes: products and prices live on the device, sales are saved locally and synced exactly once when the connection returns. No duplicates, nothing lost.
See how the Vezano Pro cashier works offline
More guides
All guidesHow to count your stock without closing the store or warehouse
The cycle-counting method: count a small part every day instead of a full closure day, approve variances before applying them, and find the cause of a difference instead of correcting it silently.
Guide6 min readHow to collect customer debts without losing the customers
A simple collection routine for retail, wholesale and distribution: a credit limit per customer, a monthly statement instead of a verbal demand, debts sorted by age, and a short list of who to call.
Guide