Taking cards offline means taking them unauthorised.
Offline mode stores transactions and submits them when the connection returns. It keeps you trading, and every transaction taken that way is one you have not had approved — so the declines, and the losses, are yours.
What this page settles.
Three questions, in the order most people ask them.
What it actually is
Offline mode — also called store-and-forward — lets a card terminal accept a transaction when it cannot reach the processor. The card is read, the details are stored encrypted on the device, and the transaction is submitted when the connection comes back.
From the counter it looks identical to a normal sale. The customer taps, the terminal approves, a receipt prints.
The terminal is not approving anything. It is recording the transaction and telling you it has done so. No bank has been contacted, no funds have been checked, no fraud screening has run.
That distinction is the entire subject of this page, and it is the one most staff using offline mode do not know.
The risk, stated plainly
You are handing over goods against an unapproved payment.
If the card is expired, stolen, closed, frozen or simply over its limit, you find out when the batch submits — by which point the customer has left with the goods. The decline is your loss. You can pursue the customer, and realistically you will not recover it.
Three things make this worse than it first sounds:
The failures cluster. A card that declines is more likely to be a card that would have declined for everybody, which means the people most likely to be affected by an outage are disproportionately the ones whose cards would not have worked.
Fraud knows about this. A business visibly operating offline is a business not checking cards, and that is not a secret.
The cost per transaction may also be higher. A transaction authorised well after it was taken can fall into a worse interchange category. Card-not-present downgrades.
What you do get: the sale, in the normal case where the card was fine — which is the great majority of them. That is a real benefit and the reason the feature exists. How a card payment works.
The limits most systems impose
Because the risk is real, implementations constrain it. Expect some combination of:
A maximum amount per transaction. Often modest — tens of dollars rather than hundreds. Large sales are the ones you least want unauthorised.
A maximum total stored, after which the terminal stops accepting offline.
A maximum number of offline transactions.
A time limit. Transactions must be submitted within a window, after which they may be rejected outright. Settling late is its own problem. Batch cutoff times.
Card type restrictions. Some implementations will not take certain cards offline at all.
Who carries the liability, which may be set by your agreement rather than by the device.
Find out your actual limits before you need them, and make sure whoever is on the counter knows them. Discovering the cap mid-outage with a queue is the wrong time.
When it is worth enabling
Brief, occasional outages in a business with small tickets. A cafe whose broadband drops for twenty minutes a month is exposed to very little and keeps serving. This is the case the feature was built for.
A mobile trade in areas with patchy coverage, where some transactions would otherwise be impossible — with the caveat that cellular is usually the better fix.
As a genuine emergency fallback, enabled with tight limits, used rarely.
At an event or a remote site where no connection exists at all and the alternative is not trading.
In all four cases the shape is the same: low value, short duration, used knowingly.
When it is not
High-ticket sales. An unauthorised $900 transaction is not a convenience, it is a gamble with a known house edge.
As a substitute for fixing the connection. If you are using offline mode weekly, you do not have an offline-mode question, you have an internet question, and the fix is cheaper than the losses.
In a business already carrying dispute or fraud pressure. Adding unauthorised transactions to an account with a chargeback problem is the wrong direction. Chargeback monitoring programs.
Where staff do not know what it means. If the person on the till thinks the terminal approved the card, they will not exercise the judgement the mode requires — which is the only control left once authorisation is gone.
For card-not-present or keyed transactions, where you have neither authorisation nor a card read.
The better answers
Three, and all of them beat accepting unauthorised payments.
Cellular backup. A terminal with a mobile data connection, or dual connectivity that falls back from wi-fi automatically, keeps you properly online when the broadband drops. Published examples run around $10 per reader per month. For any business where an outage means lost trade, this is the correct fix and it is inexpensive. Which terminal type.
A phone as a backup. Tap to pay on a phone runs on mobile data and needs no hardware, so a staff phone becomes a working, fully authorised till when the terminal cannot connect. Costs nothing to have ready.
A second terminal. For a single-till business, a spare is a few hundred dollars and covers device failure as well as connection failure.
And the unglamorous one: a better connection. Ethernet rather than wi-fi for a fixed counter removes most of the problem for the price of a cable.
What we charge
Interchange + 0.50% + 10¢ in person, interchange + 0.75% + 25¢ keyed, with no contract, no monthly fee and no monthly minimum.
If your connection drops often enough that offline mode matters, tell us about the setup. In almost every case we have seen, the right answer has been a cellular fallback costing a few dollars a month rather than a policy of accepting unauthorised cards.
While we are on the subject
Is offline mode safe?
The card data is stored encrypted, so it is secure in that sense. What is not safe is the commercial risk: you are accepting payments nobody has approved.
What happens if an offline transaction declines?
You have already provided the goods or service, so it is your loss. You can pursue the customer, and in most cases you will not recover it.
Can I disable offline mode?
Usually yes, and for some businesses that is the right choice. A terminal that refuses to trade offline cannot generate unauthorised transactions.
Does offline mode cost more per transaction?
Often, yes. A transaction authorised after the fact can fall into a worse interchange category, on top of the decline risk.