How to set purchase limits for a flash sale

A flash sale often needs both a per-order cap and a campaign-wide total sales cap. Use an order or product limit for the first and a total limit for the second. Add a purchase frequency condition only if the campaign also restricts repeat purchases by the same customer. These three controls need separate setup and tests.

Create and verify a campaign rule

1. Decide which items participate, when the campaign starts and ends, and the per-order and total sales caps. For example, allow no more than two units of Product A per order and 100 units sold during the campaign.
2. Create a product limit or order limit for Product A. Set Maximum quantity = 2 and enter the start and end times.
3. Create a total limit for Product A or for the variants that need separate counting. Set Limit quantity = 100 and review the sold, reserved, and available quantities.
4. Turn on Enable checkout validation in both rules. Under shop-level Checkout Validation, verify that the matching product or order function and the total limit function are enabled. Turn off Allow all customers to complete checkout.
5. If each customer may buy only once per day, set Frequency limit → Once per day on the applicable order or product rule. Frequency requires a signed-in account. Set up violation tags and optional email if staff need after-payment alerts.

Test both limits

With Product A, one unit should satisfy the per-order cap; three units should exceed it. Test the total limit separately by reviewing sold, reserved, and available quantities and, in a safe test environment, checking behavior when the available amount approaches zero. If frequency is enabled, first place an order that counts under the new rule, then try buying one unit again with the same signed-in account. After normal synchronization, that repeat should be blocked during the period. Record each outcome with the verification checklist.