Checkout validation (the date guard)
Updated 23 July 2026
The picker stops most bad orders in the browser. Flare's Delivery Availability & Date Guard is the server-side backstop: a Shopify checkout rule that validates the order at the moment of payment, so nothing invalid slips through — not even from surfaces where the picker can't run.
What it blocks
- Checkout with no delivery date when you require one.
- A selected date that has become invalid since it was chosen — passed its cutoff, gone over capacity, been blocked, or fallen inside your minimum lead time.
- Addresses outside your zones when delivery there isn't offered.
The shopper is asked to fix it before paying — you never receive the broken order.
Strict vs compatibility mode
In Shopify admin → Settings → Checkout → Checkout rules → Flare delivery date guard settings:
- Strict (default) — a date is mandatory for shippable checkouts.
- Compatibility — checkouts without any date evidence may proceed. Use this if you take orders through the Shop app or other surfaces where the picker doesn't run, and prefer dateless orders over blocked ones. Known-invalid states (stale date, over capacity, no zone) still block in both modes.
Custom messages
Shopper-facing copy is editable:
- In the guard's Shopify settings: the three core messages — delivery unavailable, missing date ("Please select a delivery date to continue."), invalid date.
- In Date selector → Checkout error messaging: the checkout picker's messages for address doesn't match a zone, products not eligible for delivery, and no shipping options available.
Write them like a human: "We don't deliver to this postcode yet — see our delivery areas" beats a generic error.
Do I need to configure anything?
No — the guard installs with the checkout picker and follows your existing rules. Touch it only to choose strict vs compatibility or to reword messages.