Sell offline and synchronise
Keep trading when the network drops, and understand what is queued, what is refused and how it syncs.
Before you begin
- The till has been loaded online at least once with the register open, so it has cached products, payment methods, reason codes, promotions, the profile and the session.
- The register's profile allows offline selling. If it says online only, the till says 'This operation requires a connection.'
How offline works
The header shows ONLINE or OFFLINE, the Last sync time and the Pending count. When the network is off you keep selling. Each bill is stored on the device with its own unique identifier and a receipt number made on the till (for example POS01-20261002-000001, -000002, -000003). The receipt says Queued - will sync.
After you restart the browser while offline, the till needs one online load before it can start again.
Steps: trade through an outage
- Keep selling as usual. Sell, hold bills and record cash movements.
- Watch Pending rise in the header.
- When the network returns, wait up to 20 seconds. The till sends the queue by itself and shows 'Synced 4'.
- To send at once, press Sync now.
- Check that Pending is 0.
What works offline and what does not
| Works offline | Needs a connection |
|---|---|
| Cash and card sales | Coupons ('Coupons require an online check') |
| Holds and recall | Loyalty points |
| Cash in, cash out, safe drop | Gift card, voucher, store credit |
| Opening and closing a session | QR / wallet and customer account tenders |
| Promotions marked allowed offline | Customer search (Walk-in is used) |
What the system limits
The register's profile can set limits, checked by the system from its own clock and records, so changing the PC clock does not help.
| Limit | Message |
|---|---|
Offline for too long (Offline max minutes) | 'This register has been offline for more than 60 minutes. Restore the connection before selling again.' |
Too much unsynced value (Offline max amount) | 'This sale would take the register to 2010.00 offline, which is its limit of 2000.00. Sync before selling again.' |
| Till-side check of the same limit | 'This sale exceeds the approved offline amount. Reconnect first.' |
| Online-only tender on an offline bill | 'QR / wallet must be authorized online.' |
| Fiscal profile | 'This fiscal profile requires online issuance before the receipt can be finalized.' |
| Online-only register | 'This register is not allowed to sell offline.' |
The time limit counts from the last time the system heard from the register, to the moment the bill arrives. A bill sold early in an outage can therefore be refused when it finally syncs after a long outage; the refused bill stays in the queue as failed with its reason. Reconnect before the limit when you can.
What happens on sync
- Items are applied in a safe order: session open, cash movements, sales, then session close, whatever order they were sent.
- A batch is partial: good items are saved; a bad one stays in the queue marked failed with its reason, and the rest continue.
- Duplicates are recognised. Replaying the same upload creates no second bill, stock move or journal.
- Bills are flagged Offline = Yes and appear under Point of Sale > Synchronisation > Offline audit and in the sales lists.
- Stock and Finance effects happen once.
- A batch holds at most 200 items: 'Send at most 200 items at a time.'
Worked example
Offline max amount is 100.00 AED. You have queued 90.00. A new offline sale of 120.00 is refused by the till before it is saved. Reconnect, sync, and the 120.00 can be sold online.
Good to know
- A hold made offline uploads before any recall, so another till can recall it afterwards.
- If an offline session opens while the system already has a live one for the register, the system answers with that one and no second drawer is made.
- Supervisors review queues under Synchronisation > Pending transactions and Failed sync (both menus open the same list), and the Device monitor. See Monitor tills and review exceptions.
- To protect against forged uploads, secure each device: Secure a till device.