How the hold works
- Held at add to cart. When a customer adds a time to the cart, that slot is reserved for everyone else straight away, for a hold window you set.
- Kept by the cart guard. The Booking Cart Guard runs on the cart so a held slot stays valid through checkout. It is why you turn the cart guard on.
- Rechecked at checkout. At checkout the slot is validated again, so a slot that was taken in the meantime cannot be paid for.
- Released if unpaid. If the order is not paid within the hold window, the slot is released and returns to sale, so abandoned carts never lock a time forever.
- Manual and offline payments held until you mark them paid. An order placed through a manual or offline payment method, such as cash on delivery or a bank deposit, holds its slot as soon as the order is created and keeps holding it until you mark the order as paid or cancel it. It does not release automatically the way an abandoned cart does, since the customer has already placed the order.
If two do slip through
In the rare case two paid orders land on the same slot, Booker flags the second as a conflict on your calendar so you can resolve it, and keeps that slot blocked from any further bookings.
What shoppers see at checkout
On Shopify Plus, a branded banner explains this at checkout: "This reserved time is no longer available." On every other plan, checkout still blocks the order the same way, just with the plain Shopify validation error instead of the branded banner. The block itself runs on every plan; only the branded banner needs Plus.
Good to know
Do I need the cart guard?
Yes. The Booking Cart Guard keeps held slots valid on the cart, so turn it on for every store using the calendar.
What if a customer abandons the cart?
The hold lapses after the window you set and the slot returns to sale, so an abandoned cart never blocks a time permanently.