(Use Case) Limit Quantity to 1

Use this when you want to limit purchases to 1 item per order, such as for limited-quantity products or lottery-based sales.

When customers add the eligible items to their cart (or attempt to purchase), the following behavior applies based on quantity:

• 1 item → Allowed

• 2 or more items → Not allowed

• Setting Maximum quantity to 1 prevents customers from adding 2 or more of the same variant to their cart.

• Minimum quantity can remain at 1 — no change needed.

• Since Applicability is set to Variant, different variants (e.g. S size and M size) can each be purchased in a quantity of 1. If you want to restrict the combined total across all variants, use Product instead.