“I typed the code exactly. Checkout won’t take it.”
When no discount in your store uses the code, Shopify can’t apply it. The usual causes are a typo, a code that was deleted, or one from another store.
Get notified: Coming soonNOPE123 wasn't applied. Code NOPE123 doesn't exist or can't be used.
Why it happens
Shopify looks the code up among your store’s discounts. When none uses it, there’s nothing to apply, and nothing to explain either: no settings, no dates, no minimum. That’s why this sentence is short.
NOPE123 was typed into a cart with one Hydrogen board on the lab store, 24 October 2026. Shopify knew no discount by that code, and the cart kept only “$10 off $80”.
The same $590.00 cart with another code typed gets another sentence: LABOLD10 (it expired), WAX15 (it’s for other products) and VIP20 (it’s only for some customers). Checkout shows the same $590.00 every time.
What Checkout X-Ray reads
- What Shopify reports for each code typed: applied, not applied, or not found.
- A code Shopify doesn’t find gets this sentence. A code it finds goes through the other reasons: its dates, customers, items, minimums and combinations.
What to look at in Shopify
Search Discounts for the code. If it isn’t there, compare it letter by letter with what was sent to the customer (an O for a 0 is enough), and check it wasn’t deleted. If it is there, the code exists and something else stopped it: price the cart with it in the Simulator for the reason.
The sentence Checkout X-Ray writes for this reason, filled in for each cart: Code code doesn’t exist or can’t be used.
Answer the next one with an X-ray.
Install on Shopify
Add Checkout X-Ray from the Shopify App Store. It opens in your Shopify admin, on the Free plan.
Build the customer’s cart
Open the Simulator. Pick the products, type the code they used and the country it ships to, then calculate the price.
Read the answer
The price X-ray shows each layer, and every code that wasn't applied gets a sentence saying why. Save it as a test cart to have it checked again.
