Pixel Tracking

Pixel tracking is a way of recording a conversion by loading a tiny image or script, the pixel, on a page such as the order confirmation page. When it loads, it sends the order details to the tracking provider, which matches them to the earlier click. In affiliate marketing it is the classic client-side method for crediting publishers with sales.

How pixel tracking works

When a shopper clicks an affiliate link, the network records the click and information about the publisher is stored in the shopper's browser. On the confirmation page, the pixel fires and sends the order reference, order value and stored click details to the network. Awin, CJ, Rakuten and other networks all use this pattern, usually through a JavaScript tag rather than a literal 1x1 image.

Client-side pixels depend on the browser cooperating. Ad blockers can stop them loading, and Safari's Intelligent Tracking Prevention blocks third-party cookies by default.

WebKit says cookies created in JavaScript are deleted after seven days without user interaction. They can be capped at 24 hours when a visitor lands from a link carrying click IDs. That can cut a programme's real cookie duration far below what its terms promise.

Pixel tracking vs server-to-server tracking

Server-to-server tracking moves the reporting step off the browser. The advertiser stores the network's click ID when the visitor lands, then its own server sends the conversion directly to the network. Awin requires server-to-server tracking for all advertisers, with consent signals as a separate integration. Many advertisers keep the pixel as well, deduplicating by order reference.

Example of pixel tracking loss

Imagine a retailer with 1,000 affiliate sales in a month, paying £5 commission per sale. If ad blockers, browser limits and a broken tag stop the pixel recording 10% of them, 100 sales go untracked. Publishers lose £500 in commission, and the advertiser's reports understate affiliate revenue by the value of those orders.

Why pixel tracking matters

For advertisers, tracking quality decides whether publishers trust the programme. Untracked sales mean unpaid partners, distorted attribution and weaker reasons for top publishers to keep promoting you. Test tags after every site release, checkout change or new consent banner.

For UK sites, consent is part of the picture. The ICO's guidance uses an affiliate pixel as a worked example and concludes that storing and reading the click information engages regulation 6 of PECR. New exceptions under the Data (Use and Access) Act 2025 apply from 5 February 2026, but the ICO says ad measurement and affiliation still need consent. Server-to-server tracking does not change this where the click ID is still stored in the browser.

For publishers, pixel tracking explains why some sales never appear in your dashboard. Ask advertisers whether they run server-to-server tracking before you invest heavily in promoting them.

For a wider view of how clicks, cookies and commission fit together, see the tracking section of our affiliate marketing 101 guide.