What is a tracking pixel?

A tracking pixel is a piece of code or an embedded resource that sends information to a server when it loads or when a specific action occurs. It is often implemented as a tiny, invisible image on a webpage or in an email, but modern tracking pixels can also use other types of requests.

For example, an advertising pixel on a purchase confirmation page can send a signal to an advertising platform when someone completes an order. The request may include information such as the time of the event, the type of action and identifiers that help connect the event to a particular browser or user. MDN’s explanation of web beacons describes how embedded resources can send information to servers.

A tracking pixel does not need to display anything on the screen. It can also work together with cookies or other identifiers to connect a new event with previous activity. The key difference is that a pixel is a mechanism for sending or reporting information, while a cookie is data stored in the browser that can be sent back to a server with later requests.

Tracking pixels are not automatically exempt from privacy requirements. Where their use requires consent, they should not be activated before the required consent has been obtained.