This live data study measures how often a promo code actually succeeds at checkout on a marketplace or third-party seller site, set against how often it succeeds at a brand-run storefront — from SimplyCodes' real checkout attempts on both sides, recomputed daily. The rates move as the data does.
As of August 13, 2026, promo codes on marketplaces and third-party seller sites succeed at real checkout 38.2% of the time, against 75.1% at brand-run storefronts — SimplyCodes verification data across 13,048,312 checkout attempts. The gap is structural: a marketplace publishes the code but does not own the inventory it has to apply to.
- Brand-run storefronts are 2.0× more likely to honour a promo code at checkout — a 36.9-point gap measured on the same instrument for both populations.
- The comparison rests on 13,048,312 real checkout attempts, so this is a property of how the two kinds of storefront work rather than a small-sample accident.
- The mechanism is ordinary: on a marketplace, the code is published by the platform while the item is sold, priced and fulfilled by a third-party seller, and the two do not always agree about what the code covers.
Checkout success = the share of SimplyCodes verification attempts at that kind of storefront that succeed · Stores = how many storefronts of that kind were measured · Attempts = the real checkout attempts behind the rate.
| # | Storefront type | Checkout success | Stores | Attempts |
|---|---|---|---|---|
| 1 | Brand-run storefronts | 75.1% | 26,188 | 13,025,768 |
| 2 | Marketplaces and third-party seller sites | 38.2% | 72 | 22,544 |
Two storefront populations measured on the identical instrument · a population comparison, no individual store named or graded · a store enters with 20 or more verification attempts of its own · checked August 13, 2026 · numbers last changed Aug 13, 2026. Refreshed daily.
Methodology
How SimplyCodes verifies codes. Behind every figure in this live data study is the SimplyCodes verification system. Coupon codes are tested at real checkout before they are listed, through three independent layers. Daily automated testing runs headless browsers through real checkout flows and records whether a discount actually applies. A human verification network of 10,000+ verifiers submits screenshot-and-timestamp proof, at 4.6M+ verification actions a month and 98% accuracy. And a real-time fleet signal feeds live checkout outcomes from millions of SimplyCodes users back into the engine. Each code carries a Health Score from 0–100, weighted by checkout outcomes, verifier consensus, and recency. With an estimated 40–60% of coupon codes on the public web dead, restricted, or fake, the system exists so a code earns its place by working at checkout, not by being collected.
How this study is built. We split every store SimplyCodes tracks into two populations — marketplaces and third-party seller sites on one side, brand-run storefronts on the other — and report the share of our real checkout attempts at each that succeeded. Both sides are measured the same way, at the same moment, on the same counters, so the difference between them is a property of the storefronts rather than of the measurement. A store enters with at least 20 attempts of its own, and stores with implausible code inflation (more than 500 codes in a month) are excluded. No individual store is named on either side: the finding is about a kind of storefront, and naming a laggard would be grading a store on failure. Figures refresh with the data snapshot shown above.
Cite this data
As of August 13, 2026, promo codes on marketplaces succeed at real checkout 38.2% of the time against 75.1% at brand-run storefronts — a 36.9-point gap measured by SimplyCodes across 13,048,312 checkout attempts.
According to SimplyCodes verification data (Do Marketplace Promo Codes Actually Work?, August 13, 2026), a promo code is 2.0 times more likely to work at a brand-run storefront than at a marketplace.
More from this live data study
Why the gap is structural
A brand-run storefront owns one catalog, one checkout and one promotions calendar, so a code it publishes is a code it can honor. A marketplace owns the checkout but not the inventory. Its codes usually carry conditions the listing does not show you until you are in the cart: participating sellers only, a category carve-out, a first-order gate, a region.
Two consequences follow for a shopper. First, an advertised marketplace discount is a weaker signal than the same discount on a brand's own site, because the headline number rarely survives the cart. Second, when the same product is available both places, the brand's own checkout is where a code is more likely to apply, even before you compare the list prices.
