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Cookie window (attribution window)

Also called attribution window, cookie duration, cookie life, referral period, return days.

Short answer

A cookie window, or attribution window, is the period after a click on an affiliate link during which a purchase still earns the affiliate commission. The store sets the length per program, and if the customer buys after it expires, no commission is triggered.

Definition of Cookie window (attribution window).

The cookie window, also called the attribution window, is the time between a click and a conversion during which the conversion is still attributed to the click. The window is measured from the click's timestamp to the time of the order. The name comes from the cookie that originally carried the information in the browser, but the limit itself can just as well be enforced on a server based on the click's recorded time.

Example: if the program has a 30-day window and the customer clicks on 1 March, a purchase on 25 March earns the affiliate commission. A purchase on 5 April does not – the window closed on 31 March.

The length is a point of negotiation, not a law of nature. A short window of 7 to 14 days suits impulse purchases and inexpensive products, where the decision rarely takes a week. A long window of 30 to 60 days suits expensive, researched purchases, subscriptions and B2B, where the customer reads a review, sleeps on it and only comes back after payday.

The window is tied to the click, not to the user. If the same person clicks another affiliate link in the meantime, a new window starts, and under last-click attribution the new click takes over the credit. A long window therefore does not protect against another affiliate stepping in – it only extends how long the click can count at all.

What closes the window early

The window is an upper limit, not a guarantee that measurement holds all the way. If the customer deletes their cookies, switches to another browser or buys on their phone after clicking on their computer, the click no longer exists in the chain the conversion comes in through. The order is recorded, but without a click ID, and then there is no affiliate to credit.

Browser policies set their own limit. Safari's ITP cuts the lifetime of first-party cookies set with JavaScript to 7 days, regardless of what the program has agreed. A program with a 45-day window can therefore in practice lose the part of the traffic where only the cookie carried the information, whereas a click ID in the URL and a click record on the server last longer.

How to choose a length

The store should look at the actual time from first visit to purchase in its own web analytics and set the window a little above the median. If half of all purchases happen within 3 days, little extra is gained by going from 30 to 60 days – you simply pay commission on more orders the customer would probably have placed anyway.

If an affiliate has to compare two programs, the window says less than the combination of window, commission rate and approval rate. A 45-day window with 4 % commission and half the sales rejected is a worse deal than 14 days with 8 % and almost everything approved.

Cookie window vs. approval period

AspectCookie windowApproval period
Measureshow long a click can trigger commissionhow long the store can reject a recorded commission
Starts atthe clickthe conversion
Lengthset per program; at Affilyflow between 14 and 90 days30–90 days at Affilyflow (set per program), then automatic approval
On expirythe purchase does not countthe sale is approved automatically
Who feels itthe affiliate loses the sale before it existsthe affiliate waits for money that has already been earned

The cookie window decides whether the commission arises at all; the approval period decides when it turns into money.

How it goes wrong

  • 01

    Confusing the window with the cookie's lifetime

    The program's window and the browser's cookie lifetime are two different figures. If the browser limits the cookie to 7 days, it does not help that the program terms say 45. It is the shorter of the two the user lives with in practice.

  • 02

    Changing the length mid-campaign

    If the window is cut from 45 to 14 days while content is already live, credit falls on traffic the affiliate has paid to create. Changes to the window belong in the program terms and should be announced in advance.

  • 03

    Reading a long window as low risk

    A long window only increases the number of orders that can be attributed. It says nothing about how many of them will be approved, and the approval rate decides what the window is worth.

At Affilyflow

Cookie window (attribution window) in practice

At Affilyflow, the attribution window is locked the moment the click happens. The click record gets the program's window written into it along with the commission rate and type, and when a conversion comes in, our server decides from the click's own timestamp whether the window is still open. The client cannot send a claim about how old the click is.

If the store changes the window tomorrow, the change only affects new clicks. Clicks already in the system keep the length and the rate they were recorded with.

Frequently asked questions

What is an attribution window?

An attribution window is the number of days after a click on an affiliate link during which a purchase is still attributed to the affiliate and earns commission. The window is counted from the time of the click, and a purchase after it expires earns no commission.

How long is the cookie duration on an affiliate link?

The length is set per program by the store. On Affilyflow the window is chosen between 14 and 90 days, and we recommend 30 days. The specific window is shown on the program's page before you join.

What happens if the customer clicks two different affiliate links?

Under last-click attribution the most recent click wins, as long as it is within its own window. The first click loses the credit, even though its window is still open.

Do I get commission if the customer buys the day after the window expires?

No. The window is a hard limit, decided from the click's timestamp. An order that lands outside the window is recorded without commission to you.

Can the store shorten the cookie window after I have published my links?

The store can change the window going forward, but the change only applies to new clicks. Clicks that are already recorded keep the window they were locked with.

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