Coupon-code affiliates vs link affiliates: run both, differently
What the numbers say
- 01
Modelled incrementality runs from 8% for browser coupon extensions to 68% for customer referral links, a more than eightfold spread.
Modelled on stated assumptions: the share of attributed orders that would not have happened without the partner.
- 02
A single flat commission across all partner types overpays extension traffic by roughly 8x relative to what its incrementality supports.
Derived from the incrementality spread applied to a uniform rate.
- 03
Deal and coupon communities model at 22% incrementality against 55% for content and review sites.
Modelled on stated assumptions comparing discount-seeking audiences with research-led ones.
- 04
A public code stops identifying the partner it was issued to within days, once it is republished on aggregator sites.
Derived from the code leakage mechanic described in this article.
- 05
Commission scaled to incrementality gives a modelled range from 1% to 12% across the six partner types, against a typical flat 10%.
Derived from the recommended rates in the comparison table.
The affiliate report has one number for the channel and one commission rate underneath it. Inside that number are a woman who reviewed the product on YouTube for eleven minutes and a browser extension that fires four seconds before checkout.
They are being paid the same 10%. (Composite, drawn from programs we have audited.)
One line item, two businesses
Coupon affiliates and link affiliates get bundled because they are both partners who get paid per sale. Almost nothing else about them matches.
Link affiliates operate before the decision. They introduce the product to somebody who had not considered it, which is acquisition.
Coupon affiliates mostly operate after it. They intervene between a decision already made and the transaction that follows, which is a service to the shopper and something quite different from acquisition.
The spread is measurable, and it is wide enough that one rate across both is not a simplification but an error.
Incrementality by partner type
Modelled incrementality, meaning the share of attributed orders that would not have happened without the partner.
| Partner type | Modelled incrementality | Where they operate |
|---|---|---|
| Customer referral link | 68% | Before the decision, personally |
| Creator or influencer link | 62% | Before the decision, at scale |
| Content or review site | 55% | During consideration |
| Deal and coupon community | 22% | After intent, before choice |
| Cashback site | 15% | After the decision |
| Browser coupon extension | 8% | At checkout |
More than eightfold between top and bottom.
That spread is not a criticism of the bottom rows. A cashback site provides a genuine service and its users like it. It is simply not doing the thing a 10% acquisition commission is meant to pay for.
Why the extensions score so low
The mechanic explains the number.
A shopper reaches checkout with a full cart, clicks the discount code field, and an extension detects it, tries a list of codes, and fires a redirect that sets a last-touch cookie in the process.
Everything that produced that cart already happened. The ad, the search, the email, the friend. The extension arrived after all of it and collected the credit, which is the last click problem quantified in affiliate attribution: last click is lying to you.
Cashback sites score slightly higher because the shopper deliberately routed through them, which reflects intent even though it does not create it. Deal communities score higher again because a discount-seeking audience does occasionally discover a brand there.
Commission scaled to incrementality
| Partner type | Modelled incrementality | Suggested commission |
|---|---|---|
| Customer referral link | 68% | Chain at 8%, 4%, 2% |
| Creator or influencer link | 62% | 10% to 12% |
| Content or review site | 55% | 10% |
| Deal and coupon community | 22% | 4% |
| Cashback site | 15% | 3% |
| Browser coupon extension | 8% | 1% to 2%, or excluded |
The range runs from 1% to 12% against a typical flat 10%.
Under a flat rate, the least incremental partners are the best paid relative to what they contribute, and they are also the ones who will grow fastest, because interception scales more easily than making content does.
Check every rate against your own margin before adopting it. The ceiling that decides what any structure can afford is worked through in the affiliate commission structures that survive a margin review.
SB&R is a Shopify app for chained referral rewards. Every referral link belongs to someone who has already bought. When a new customer buys through that link, coins cascade to everyone up the chain, as far as the brand configured. Coins redeem as a capped checkout discount and are never paid out as cash.
Customer referral sits at the top of the incrementality table for a structural reason. The link comes from a person the recipient knows, which is a recommendation rather than a placement.
Attribution priority, and the code caveat
Korant is a multi-tenant attribution platform that tracks influencer, SEO, and affiliate marketing performance. Every influencer, publication, and affiliate gets a unique redirect slug. Korant records first-touch and last-touch attribution cookies, resolves sales through a documented priority order, and reports across brands for agencies managing multiple clients.
Codes rank above cookies in a sensible priority order, because entering a code is an explicit act by the shopper while a cookie is an inference about them.
That ranking holds only while codes stay non-public. A code that has been republished on an aggregator site is no longer an explicit act by that partner’s audience, and leaving it at the top of the priority order hands your best-ranked signal to whoever found the string.
So the code step carries a maintenance obligation. Search monthly for your brand name plus the word coupon, compare what appears against the codes you issued, and retire anything that leaked.
Korant is not for stores with a single paid channel, or for brands that only need Shopify’s native reports. With one partner type there is nothing to prioritise between.
The offer that cannot leak
For genuinely exclusive partner offers, the answer is to stop using strings.
FlashPin is a multi-tenant Shopify app that rotates which delivery pincode has a live discount on a cadence the brand sets. Shoppers in the live pincode get the discount applied automatically at Shopify’s own checkout with no code to enter and no redirect. Referring a friend earns coins in a wallet that can be spent on any future order.
Pair a partner with a live zone during their campaign and the offer is tied to where the parcel is going rather than to a code anybody can republish. There is nothing for an extension to try and nothing for an aggregator to index.
This works in proportion to how geographically concentrated the partner’s audience is, which makes it a fit for city-focused creators and local businesses and a poor fit for a national content site.
Terms that differ by type
Run both types in one program, with different terms.
Link affiliates: standard commission, standard cookie window, code optional.
Coupon and cashback partners: lower commission, shorter cookie window, and an explicit term that trademark bidding and brand-term search are out of scope. That last clause matters more than the rate, because bidding on your own brand name is the other way this category collects credit for demand it did not create.
Extensions: decide deliberately whether to be in their network at all. Some brands conclude the reach is worth a low rate; others conclude they are paying a toll. Both are defensible, and drifting into it without a decision is not.
What the incrementality numbers are not
Every figure here is modelled from stated assumptions rather than measured across a panel of stores. The ordering is the finding; the decimals are illustration.
The way to get your own numbers is a holdout: pause one partner type in a matched geography for eight to twelve weeks and compare total orders rather than attributed ones. It costs real money and it is the only method that answers the question.
Almost nobody runs one, which is why commission rates in this channel are set by negotiation rather than by evidence, and why a partner type with 8% incrementality can spend years being paid as though it had 68%.
Questions people actually ask
Should affiliates get a coupon code or a tracking link?
A link always, and a code only when the audience genuinely needs the incentive to convert. Codes measure code entry rather than influence, they leak to aggregator sites within days, and they force a discount onto a campaign that may not need one. Read the link for attribution even when a code is running.
Do coupon sites and browser extensions produce incremental sales?
Very few. Modelled incrementality is 8% for extensions and 15% for cashback sites, because both intervene after the purchase decision has been made. They provide a real service to the shopper and are close to a toll on demand you already created.
Should coupon affiliates be paid less than link affiliates?
Yes, and the gap should be large. On modelled incrementality, extension traffic supports roughly 1% to 2% commission against 10% to 12% for creators and content sites. Paying one rate across both means the least incremental partners are the best paid relative to what they contribute.
How do you stop a partner code leaking to coupon sites?
Keep partner codes non-public, monitor for your brand name plus the word coupon monthly, and retire any code that appears. For genuinely exclusive offers, gate on something a shopper cannot type at all, such as the delivery address, so there is no string to republish.
Can one program run both types?
It should, with different rates, different attribution priority and different terms. What fails is one rate, one set of terms and one report, because the average across two channels with eightfold different incrementality describes neither of them.