Glossary
Cookie window
How long a tracking cookie stays valid after it is set. Often confused with the attribution window, which is a reporting rule rather than a storage limit.
Also called: cookie duration, cookie lifetime
A cookie window is a storage question: how long does this cookie survive before the browser discards it?
An attribution window is a reporting question: how long after an interaction will the report still credit that interaction?
The two get used interchangeably and they are not the same. A cookie can outlive the window that would have credited it, and a conversion can fall inside an attribution window even though the cookie that identified the user is long gone. Affiliate programmes usually mean the first when they advertise a generous cookie window; ad platforms usually mean the second.
The complication is that the browser has the final say. Whatever expiry you set, tracking prevention in the major browsers can shorten or ignore it — particularly for cookies set by scripts rather than by your own server. So the number in the settings panel is a ceiling, not a promise, and it applies to some visitors and not others.
That is why an affiliate programme’s advertised cookie window is closer to a marketing figure than a technical guarantee. It describes their intent. The actual retention depends on the browser, the platform, and whether the visitor cleared anything in between.
If you need something durable, the answer is not a longer cookie. It is an identifier that does not depend on one — a click ID carried through the funnel, or a first-party record keyed to something the customer gave you.
Do not confuse with
Close enough to get mixed up, different enough that the mix-up costs something.
- Attribution window The period after an ad interaction during which a later conversion is still credited to that interaction. Once it closes, the conversion is counted as coming from somewhere else.
- Click ID A unique identifier an ad platform appends to the landing page URL when someone clicks an ad, so a later conversion can be tied back to that exact click.
- Consent mode A mechanism that tells tags whether a visitor consented, so they adjust behaviour instead of firing or not firing. Consent is the permission; consent mode is the plumbing.
- Tracking prevention Browser features that limit how long identifiers survive and which requests are allowed, applied by default to everyone. Separate from consent, and not something the visitor opted into.