Yes, if it serves many of your customers, but never front and center. A prominent field tells anyone without a code that a better price exists somewhere, and some of those shoppers go looking for it.
The Baymard Institute observed this in user testing: most participants pause at the field, a few leave the site to find a code, and once they've left checkout, their chances of coming back drop sharply.
We weren't immune to the reflex. This spring, in an audit of a store we advise, we had listed "add a promo code field to the cart" as a quick win, estimated at one hour of work.
In the same store's backlog, another line went further: a "First order? 10% off with code BIENVENUE10" banner and a pre-filled field. The second line had understood something the first one missed: when the answer to the field is on the page, nobody leaves the site to find it.
The benchmark
Two reports are enough. The first is in Shopify: the sales by discount report shows, code by code, how many orders used it.
Divide that number by total orders over three months, keeping in mind that an order stacking two discounts appears twice.
The second takes a minute. Type "[your brand] promo code" into Google and see who answers. If the first page is full of coupon sites listing your codes, your brand name is a gateway to another site, used by customers who are ready to buy, at the moment the field gave them the idea of a discount.
The rule
If few orders use a code, make the field discreet where you control it, in the cart, behind a simple "Have a code?" link. If many do, make sure no one has to type anything, with a campaign link that applies the discount or an automatic discount.
On Shopify, checkout shows the field as soon as at least one discount code is active, and the platform still offers no official setting to collapse or hide it. So your room to maneuver is upstream, in the number of codes in circulation and in how the discount reaches the cart.
The steps
- Measure. Calculate the share of orders with a code over three months, code by code.
- Clean up. List the active codes and deactivate those with no campaign behind them, because a generic code with no end date eventually gets shared around.
- Links. Replace generic codes with shareable discount links: Shopify applies the discount to the cart on click, with no typing.
- Display. Show current offers on the product page or in the cart, so no one has to find them on another site.
- The line for leadership.
"This quarter, X orders attributed to coupon sites carried our newsletter code, and on each one we paid for both the discount and the commission."
The trap
Paying twice. A customer who has already decided opens a promo code site, clicks a code and comes back to buy.
You grant the discount, and if that site is part of your affiliate program, it also earns a commission: platforms generally credit the sale to the last click before purchase, and a coupon site sits exactly at that point in the journey.
As we read it, it then claims a sale the brand had already made.
To check, cross-reference the affiliate platform's export with the codes used, looking for orders attributed to a coupon site but placed with a code you never gave it.
