Guides · Discount codes

How to tell if your Shopify discount code leaked, using your own orders

Updated 14 September 2026 · SegmentIQ team at Marvel Labs · How the figures are calculated

A code you gave to one influencer or one email list can end up on coupon sites and browser extensions within days. Then shoppers who were already at checkout get a discount they were never meant to have. Before you pay for a leak-blocking app, your own order data can tell you whether it's actually happening.

The signs a code has leaked

• Redemptions jump without a reason. The code suddenly gets used far more than usual, on days when you didn't send an email or post about it.
• A wave of one-off email addresses. Shoppers who find a code on a coupon site usually aren't on your list and have never ordered before, so the code's redemptions shift heavily towards first-time buyers.
• First-time buyers on a code meant for existing customers. A "thank you" code for your email list shouldn't be redeemed mainly by people who've never bought before.
• It keeps being used after the campaign ended. Weeks after the send or the influencer post, the code is still going.
• It shows up online. Search for your store name plus "discount code" or "coupon" and see what comes back.

One sign on its own isn't proof. A popular influencer post also brings a spike of new customers. Several signs together on the same code are worth acting on.

Check 1: redemptions over time

In your Shopify admin, open Analytics, start a new exploration and open the ShopifyQL editor. This shows orders using a code, day by day, and how many were first purchases:

FROM sales
SHOW orders, orders_first_time
WHERE discount_code = 'INFLUENCER30'
TIMESERIES day
SINCE -90d UNTIL today

Look for days with a jump in orders that you can't tie to something you did. Compare them with your campaign dates.

Check 2: who redeemed it

Your orders export shows each redemption's email address, so you can see whether a code went to people who already buy from you or to a stream of new addresses.

1. In Orders, click Export and download the CSV for the period the code was live, plus several months before, so returning customers are recognised.
2. Drop the file into the free Discount Code Checker. For every code it shows the share of redemptions from first-time buyers and the share of the discount that went to customers who had recently paid full price. The file stays in your browser.
3. Compare codes. A code meant for a small, known audience with a much higher first-time share than your welcome code stands out, especially if those orders arrived in a burst.

For example, in the checker's sample file for a fictional tea shop, nearly every INFLUENCER30 order comes from a first-time buyer, most of them arriving weeks after the influencer's post, while the loyalty code goes almost entirely to regulars.

Check 3: search for it

• Search for "your store name discount code", "your store name coupon" and the code itself.
• Check the big coupon sites for your store's page.
• At checkout in a private browser window, look for coupon extensions offering to apply a code.

What a leak really costs

Not every redemption of a leaked code is lost money. Some shoppers found your store through a coupon site and wouldn't have bought otherwise. The costly ones are shoppers who were already on your checkout page and would have paid full price, then went looking for a code. You can't tell those apart order by order, which is why the first-time and recent full-price shares are useful: they show which way a code leans.

How to stop a code leaking

• Retire the leaked code and give the intended audience a new one.
• Set limits. In the discount's settings, under Maximum discount uses, cap the total number of uses and limit it to one use per customer.
• Restrict who can use it. Make a discount available only to specific customer segments, for example your email subscribers. Shopify can then only apply it to existing customers who match.
• Use unique codes for influencers and affiliates. Single-use codes, created with a bulk code generator or your email platform, can't be shared usefully.
• Always set an end date for campaign codes.
• If leaks keep happening, apps that block coupon extensions at checkout are worth a look, now that you can measure whether the problem is big enough to pay for.

Order data shows who used a code, not why. Treat these signals as a reason to investigate and tighten the code, not as proof of how much a leak cost.

Related: How to track Shopify discount codes by new vs returning customers · Discount cannibalization on Shopify