Privacy & Tech

What is the difference between tracking pixels and cookies?

A tracking pixel reports an interaction to a server, while a cookie stores information in a browser. They serve different functions but frequently work together.

Aspect	Tracking pixels	Cookies
Main function	Report an event through a network request.	Store information that can be used across requests or visits.
Typical example	Reporting that a purchase confirmation page loaded.	Remembering a session or tracking identifier.
How information is transmitted	Loading the pixel or executing its code triggers a request.	The browser includes eligible cookies in matching requests.
Relationship to tracking	Can report activity with or without a cookie identifier.	Can support tracking, but also functions such as login sessions.

For example, a pixel may report a purchase and a cookie may identify the browser associated with it. Whether the cookie accompanies the request depends on its settings and browser restrictions, as explained in MDN’s guide to HTTP cookies.

When reviewing website tracking technologies, inspect both cookies and outgoing requests. A website can transmit tracking information even when no new cookie appears.