What Is an Affiliate Tracking Cookie?
An affiliate tracking cookie is a small file stored in a visitor's browser after they click a partner's link, holding the partner's identifier so a later purchase is credited to them. It lasts for the program's cookie window (30 to 180 days in programs checked here) unless the browser deletes it first. First-party and server-side tracking outlast third-party cookies.
What the cookie does
When a visitor clicks an affiliate link, the link carries an identifier for the partner, and often for the specific click. The merchant's site or tracking software reads that identifier and writes it into a cookie with an expiry date. If the visitor buys before the cookie expires, the checkout or conversion event reads the cookie and the sale is credited to that partner. The cookie itself earns nothing; it is a memory of who sent the visitor.
First-party versus third-party cookies
A first-party cookie is set by the domain the visitor is on, the merchant's own site. A third-party cookie is set by a different domain, typically a tracking network loaded in a script or redirect. Third-party cookies are what browsers restrict most heavily, because the same cookie can follow a person across many sites.
Modern affiliate software generally reads the identifier from the landing URL and sets a first-party cookie on the merchant domain. That is more durable, though not immune to browser limits, and it keeps the referral data with the merchant rather than a network.
How long affiliate cookies last
The program chooses the window, and it is part of the commission terms. On vendors' own pages, checked 22 October 2026: Shopify tracks referrals for 30 days from the click, beehiiv's cookies are valid for 60 days, Webflow uses a 90-day window, Semrush 120 days, and HubSpot 180 days. A longer window credits more of the sales a partner influenced, especially for slow B2B purchases.
The stated window is a maximum. The browser can delete the cookie sooner, and under last-click attribution a newer affiliate click can overwrite it.
What browsers do to tracking cookies
Each major browser engine now limits cookies differently, and the limits apply whatever window the program advertises.
Safari
WebKit's tracking prevention documentation states that Intelligent Tracking Prevention blocks all third-party cookies by default, with no exceptions. It deletes cookies created in JavaScript, and other script-writeable storage, after 7 days without user interaction with the site. When a visitor arrives from a domain classified as having cross-site tracking capabilities via a decorated link, ITP caps JavaScript-created cookies on the landing page to 24 hours. Cookies set in HTTP responses from third-party CNAME or IP-cloaked servers are capped at 7 days.
Firefox
Mozilla rolled out Total Cookie Protection by default to all Firefox users in June 2022. It gives each site its own cookie jar, so a cookie set by embedded third-party content on one site cannot be read on another.
Chrome
Google abandoned its plan to phase out third-party cookies. In April 2025 it said it would keep its existing approach of letting users choose in settings and would not roll out a standalone prompt, as TechRepublic and others reported. On 17 October 2025, Anthony Chavez, VP of Privacy Sandbox, wrote that Chrome will maintain that approach, and announced the retirement of several Privacy Sandbox technologies, including the Attribution Reporting API, Protected Audience and Topics, citing low adoption. Third-party cookies therefore still work in Chrome for users who have not blocked them.
Server-side alternatives
Because cookies can vanish, robust programs pass the click identifier to the server and store it there. Common approaches:
- Server-side conversion events: the merchant's backend sends the conversion, with the partner or click ID, directly to the tracking system, instead of relying on a browser pixel.
- Referral codes: the buyer enters or carries a partner code at signup or checkout, which needs no cookie.
- Account-level binding: the partner identifier is saved on the customer account at signup, so every later payment, renewal and upgrade is credited by looking up the account.
HyypeFi uses the last approach: referral codes bind at signup and hold through the customer lifecycle, with payments arriving through an events endpoint or Stripe relay.
Cookies and fraud
Cookies can also be abused. Cookie stuffing drops an affiliate cookie on a visitor who never chose to click the link, so the fraudster is credited for sales they did not influence. Programs detect it through patterns such as many credited sales with almost no real clicks, or conversions seconds after a forced redirect, and by paying on verified revenue rather than on cookie presence alone.
Frequently asked questions
- Do affiliate cookies still work in 2026?
- Partly. First-party cookies set on the merchant's domain still work in every major browser, subject to limits such as Safari deleting JavaScript-set cookies after 7 days without interaction. Third-party cookies are blocked by Safari and partitioned by Firefox, while Chrome still allows them unless users block them. Server-side tracking avoids these dependencies.
- What happens when an affiliate cookie expires?
- Once the cookie expires or is deleted, the visitor is no longer linked to the partner in that browser. If they buy later without clicking another affiliate link or entering a referral code, the sale is not credited to anyone. This is why programs with long sales cycles favour longer windows or account-level attribution that does not depend on the cookie.
- Can two affiliates' cookies conflict?
- Yes. If a visitor clicks links from two affiliates, the program's attribution rule decides who is paid. Under last-click, the newer cookie usually overwrites the older one, so the most recent partner wins. Under first-touch, the original partner keeps the credit. Some programs split credit. The rule should be stated in the program terms.
- Do affiliate cookies need consent?
- It depends on the jurisdiction and the cookie's purpose. In the EU and UK, the ePrivacy rules require prior consent for any cookie that is not strictly necessary to provide the service, and affiliate tracking is generally not treated as strictly necessary, so consent is normally needed before the cookie is set. Programs should describe referral tracking in their privacy policy and follow local rules. Storing only a referral identifier against an account, server-side, usually touches less data than third-party tracking networks, though a partner ID tied to an identifiable account is still personal data under the GDPR.