What is affiliate tracking? How links, cookies, sub IDs and postbacks record a sale

What affiliate tracking is and who does the recording

Affiliate tracking is the system that records a click on an affiliate link and matches it to a later purchase, so the sale is credited to the affiliate who sent the visitor. Awin, an affiliate network, describes it as monitoring the customer journey from the click to the completed purchase.

Two parties can do the recording. The network does, because its record decides who gets the credit. The affiliate can also run a tracker of their own, to learn which ad, page or email produced each sale. Sub IDs and postbacks join the two records.

How a link, a cookie, a sub ID and a postback record one sale

1. The link carries your ID. An affiliate link names the affiliate and the seller. ClickBank's HopLink, for example, contains the account nickname of both.
2. The click is stored. When a visitor clicks, a tracking cookie or a server-based method stores the affiliate's information, as Awin describes it.
3. A sub ID adds your own label. You can attach your own tag to the link, such as the page or ad it sits in. ClickBank calls this a tracking ID and uses the parameter tid. ShareASale uses afftrack and LinkShare uses U1.
4. The sale is matched. When the visitor buys, the seller's tag, pixel or server reports the order to the network, which matches it to the stored click.
5. A postback tells your tracker. If you gave the network a postback URL, it sends an automated notification there when the transaction happens. ClickMagick's documentation says this lets the tracker record the sale against the click that produced it.

Worked example: two ClickBank links with tracking IDs

Say [your site] promotes one ClickBank product in a blog post and in a newsletter. ClickBank's HopLinks guide gives this link format:

https://hop.clickbank.net/?affiliate=[your nickname]&vendor=[seller nickname]&tid=blog_oct

The newsletter link is identical except that it ends in tid=email_oct. ClickBank allows up to 100 characters in a tracking ID, made of numbers, lowercase letters and underscores, and says the ID is visible only to the affiliate.

A reader clicks the blog link and later buys. ClickBank matches the order to the click and passes blog_oct into its reporting with the sale. At the end of the month you can sort sales by tracking ID and see how many came from each place. The affiliate ID alone cannot tell you that, because it is the same in both links.

Add a tracker and one more step happens. ClickMagick's Affiliate Link Builder rewrites the link so that it carries a visitor ID, and the network then notifies ClickMagick of each sale. For a network with standard postbacks, such as MaxBounty, you paste the URL from ClickMagick's Postback URL Tool into the network's Global Postback setting once. ClickBank uses its own Instant Notification Service instead.

Why cookies alone miss sales and what postbacks fix

Cookie-based tracking depends on the visitor's browser, and browsers limit cookies. WebKit, the browser engine used by Safari, documents that it blocks all third-party cookies by default and deletes cookies created in JavaScript after 7 days without the user interacting with the site. Awin adds that client-side tracking can be blocked by privacy settings or ad blockers.

Server-side tracking takes the browser out of the last step. Awin describes it as data sent directly between the seller's server and the network's server, which keeps working when cookies are blocked. A postback is the same idea pointed at the affiliate: the network's server calls your tracker's URL. ClickMagick's documentation calls postback URLs the most accurate way to track affiliate sales.

Some programs offer neither pixels nor postbacks. ClickMagick notes that Amazon is one, so sub IDs, which Amazon calls Tracking IDs, are the only option there. The pixels versus postbacks guide compares the methods.

Mistakes to avoid when you set up affiliate tracking

• Characters the network rejects. ClickBank's guide warns that a dash in a tracking ID breaks it and the ID will not be tracked. Use underscores.
• The wrong postback type. ClickMagick's guide says to choose the option labeled URL or Postback URL in the network account, and never pixel, iframe, HTML or JavaScript.
• A copied example URL. The same guide says your postback URL differs from the examples in the documentation, so copy the one generated in your own account.
• Sending ad clicks straight to an affiliate link. ClickMagick's documentation cautions that this is against the rules of most major ad networks, including Google Ads and Facebook Ads.

When a paid affiliate tracker is worth paying for

If you place links in content and do not buy ads, the network's report with one sub ID per page is enough. Google Analytics 4 can add click counts for links that lead away from your site.

A paid tracker is worth it once you pay for traffic. You then need to know which ad or keyword produced each sale, and that takes a click record of your own joined to the network's postback. As read on 3 October 2026, BeMob lists a Free plan with 100,000 events a month, and ClickMagick Starter costs $79 per month on monthly billing for 10,000 tracked visitors, with a 14-day free trial. Prices can change. The affiliate link tracker comparison sets six tools side by side, and the ClickMagick sub ID guide and postback URL guide cover setup in that tool.