Do card machines work without WiFi or signal?
Without WiFi, yes: most modern terminals carry a 4G SIM, and phone-paired readers use the phone's data. Without any signal at all, mostly no. A card payment has to reach the cardholder's bank to be authorised, and only a handful of devices will store a payment and send it later. Square states its Terminal can do that for up to 24 hours; Expert Market reports Dojo terminals have no offline mode and need a connection. For a field, a cellar or a basement, the question is which network reaches it, not whether there is WiFi.
WiFi, mobile data and offline are three different things
People ask about WiFi because that is the connection they can see. A card machine does not care how it reaches the internet, only that it does. There are three situations worth separating.
No WiFi, but mobile signal: a terminal with a SIM, or a reader paired with a phone, works normally
Patchy signal: payments take longer and some time out; a device with both WiFi and 4G will switch between them
No connection of any kind: only a device with a true offline mode can take a payment, and it is stored rather than authorised
Which devices connect how
| Device | Connectivity | Offline mode | Battery |
|---|---|---|---|
| Dojo Go / Go Max | WiFi + 4G SIM | No offline mode (Expert Market) | c. 10 hours (review sites) |
| Dojo Pocket | WiFi + 4G SIM | No offline mode (Expert Market) | c. 12 hours (review sites) |
| Dojo Wired | WiFi + Ethernet, mains power | No offline mode (Expert Market) | Mains |
| Square Terminal | WiFi or Ethernet | Up to 24 hours (Square) | Rechargeable |
| Square Reader, SumUp Solo Lite, Zettle Reader | Bluetooth to phone; uses phone data | Depends on app; check provider | Reader + phone |
| Tap to Pay on iPhone | Phone data or WiFi | No | Phone |
Square Terminal from squareup.com. Dojo connectivity and offline status from Expert Market and other review sites; Dojo's own site could not be verified. All checked August 2026.
4G SIM terminals
The Dojo Go, Go Max and Pocket all carry a 4G SIM alongside WiFi, per the review sites we checked, with the Go Max described as having 4G backup. In practice the terminal sits on WiFi when it has it and falls back to mobile data when it does not. The SIM is part of the package rather than something you sort out yourself. The Dojo Wired is the exception: WiFi and Ethernet, mains power, built for a counter that never moves. Device detail on our Dojo Go and Dojo Pocket pages.
Phone-paired readers
A Square Reader, SumUp Solo Lite or Zettle reader has no connection of its own. It talks to the app over Bluetooth, and the app talks to the provider over whatever the phone has. That makes the phone the weak point: if it has no signal, neither does the reader. The upside is that you can pick the phone and the network, and swap SIMs or phones if one network is dead at the venue.
Offline mode
Square states that its Terminal can accept offline payments for up to 24 hours, storing them on the device and submitting them once it reconnects. That is a genuine feature and a real advantage in a dead zone, with one caveat: an offline payment has not been authorised. If the card declines when it is finally submitted, or the device is lost before it reconnects, the money does not arrive. Expert Market reports that Dojo has no offline mode and requires some kind of connection. For other providers, check the help pages rather than assume.
Events, markets and festivals
This is where the question usually comes from, and the answer is planning rather than hardware.
Check network coverage at the site before the day. Ask the organiser which networks worked last year; a showground that is fine on one network can be dead on another
Carry two connections. A 4G terminal plus a phone-paired reader on a different network covers most outages
Charge everything the night before and bring a power bank. Review sites put Dojo Go battery at around 10 hours; a long day outdoors with a printer running will test that
If you rely on a phone, turn off WiFi auto-join. Public WiFi that connects but does not pass traffic is worse than none
Have a fallback for a total outage: a cash float, a QR code to a payment link, or an offline-capable device for small sales
For one-off or seasonal events, short-term hire avoids a contract you do not need. DNA Payments advertises short-term subscriptions from as little as one week; Rapyd advertises hire from three days to three months, aimed at festivals, exhibitions and seasonal peaks. We cover the options on our events and festivals page, and the stallholder case on card machines for market stalls.
When a 4G terminal is not the answer
If your pitch has no mobile signal on any network, a SIM does nothing for you and the only devices that will take a card are those with an offline mode, used with eyes open about the risk. If you trade a few times a year, a contract terminal is more commitment than the problem deserves; a phone-paired reader with a published flat rate, or a short-term hire, fits better. And if your premises are indoors with solid broadband, the Wired terminal on Ethernet is steadier than any wireless option and cheaper to run.
For a mobile trade that does have signal, a terminal with WiFi plus 4G is the simplest set-up we know of. Dojo pricing is quoted individually for each business; for higher card volumes a quote is often the lower option, and the only way to know is to compare a quote against your current statement. Our mobile card machines page covers the trade-offs.
Trading outdoors, on the move or somewhere with awkward signal?
Tell us where and how you sell. We will say which device fits and introduce you to Dojo for a quote.
Get a Dojo quoteCapExpand is an authorised Dojo partner and is paid by Dojo when a business signs up through us. That does not change the price you pay.
Frequently asked questions
Can a card machine work without WiFi?
Yes, if it has its own mobile data connection. The Dojo Go, Go Max and Pocket include a 4G SIM alongside WiFi, so they take payments anywhere there is mobile signal. A card reader that pairs with your phone uses the phone's data instead. What no device can do is authorise a payment with no connection of any kind, unless it has a true offline mode.
Can a card machine work with no signal at all?
Only with an offline mode, and only for a limited time. Square states its Terminal can take offline payments for up to 24 hours, storing them and processing them once it reconnects; the payments are not confirmed until then. Expert Market reports that Dojo terminals have no offline mode and need some kind of connection.
Is an offline card payment safe to accept?
It carries risk. An offline payment has not been authorised by the cardholder's bank, so it can fail when it is later submitted, for example if the card is declined or the device is lost before reconnecting. Use it for small sales when you have no alternative, and reconnect as soon as you can.
What is the best card machine for a festival or outdoor event?
A standalone terminal with a 4G SIM and a long battery, or a reader paired with a phone that has good signal on the site. Check which mobile networks cover the field before you go. For one-off events, short-term hire is available: DNA Payments advertises subscriptions from one week and Rapyd from three days to three months.
Does Tap to Pay on iPhone work without WiFi?
It works over the phone's mobile data, so it needs signal but not WiFi. SumUp, Square, Zettle and Dojo all offer Tap to Pay on iPhone in the UK. We have not seen any provider publish an offline mode for it, so with no signal at all expect it not to authorise a payment.
Device features change with software updates. Offline and connectivity details were checked in August 2026 against the sources below; confirm with the provider before relying on them at an event.
Sources (checked August 2026)
- Square Terminal: WiFi or Ethernet, offline payments up to 24 hours
- Expert Market Dojo review: no offline mode, Pocket and Wired connectivity (review site)
- Mobile Transaction Dojo review: Dojo Go WiFi + 4G SIM, battery (review site)
- MerchantHQ: Go Max 4G backup, Pocket battery (review site)
- SumUp: Tap to Pay on iPhone and Android in the UK
- DNA Payments: short-term subscription from one week
- Rapyd: card machine hire from 3 days to 3 months
CapExpand Ltd (Company No. 14433858) is an authorised Dojo partner, not a card machine manufacturer. We are not currently authorised or regulated by the Financial Conduct Authority. Card machine pricing and availability are subject to change. All information on this page is for general guidance only.