Offline card sales let the Door POS app take a card when the venue's internet is down: the card is read on the device and the charge goes through once the connection comes back.
It is off at every venue until you turn it on. Go to AdminVenues[venue]Edit and open the POS → Offline card sales card. You need the Venue settings permission.
The two settings
Allow offline card sales — off by default. Turning it on puts the Sell offline → Card option on this venue's Door POS devices.
Per-sale cap — the most one offline sale may charge. The default is $250. Stripe's own offline maximum is $10,000 per sale; a higher figure here is clamped to that.
Click Save offline card settings.
The Stripe Location requirement
Below the two settings, the card shows a read-only Stripe Location offline mode badge — On, Off, or Unknown.
This is a second switch, on Stripe's side, set in the Stripe Dashboard under Terminal → Configurations. A reader still needs offline mode on at its Location to take a card with no internet, even when your toggle above is on. If the badge reads Off, the venue setting alone will not make offline card sales work — ask Noctern support, who set up Terminal Locations on your behalf.
The risk you are accepting
An offline card sale is taken on trust: the card is read at the door, but it is not authorised until the connection returns.
A declined or failed offline sale is never voided automatically. It appears under Box Office → Incomplete Orders for you to chase. The guest has already been let in; recovering the money is your job.
That is what the per-sale cap is for. Set it to the largest amount you are prepared to lose on a single transaction that turns out to be bad — for most venues that is a normal pair of tickets, not a group booking.
What staff do at the door
Once this is on, door staff see Sell offline on the POS and can choose Card. The flow, the receipt and the reconciliation afterwards are covered in "Take Card Payments With No Internet".
Turn it on with a $100 cap, save, and read the Stripe Location offline mode badge. If it says Off, nothing will work at the door yet — note that before your next show, not during it.