In many shops an internet outage means selling stops: the till "loads", the queue grows, and staff start writing bills on paper — half of which are never entered. It doesn't have to be that way.
What "works offline" really means
Selling doesn't need the server in that moment. The till keeps the items and prices on the device, records the bill locally at once, and prints it if needed.
How bills upload later without duplicates
Each bill gets a unique ID the moment it's created on the device. When the connection returns, the till sends the waiting bills, and the server recognises any bill it has already received, so it is never recorded twice. That's why sales don't double in reports even if the device retries several times.
What about stock and points?
When bills upload, stock is deducted and customer points are calculated just as if the sale happened online. The timeline stays correct because each bill keeps the time it was sold, not the time it uploaded.
Signs of a good system
- Selling continues with no errors or waiting.
- The number of waiting bills is clearly shown.
- Bills upload by themselves when the connection is back.
- No bill ever appears twice in reports.
Test it before you buy
Ask any vendor to unplug the internet, ring up five bills, reconnect, then open the report. If you see exactly five bills, the system can be trusted.
Sijiliati has worked this way from day one. See how it works or try it on demo data.