What is a tracking pixel?

A tracking pixel (also called 1x1 pixel or pixel tag) is a graphic with dimensions of 1x1 pixels that is loaded when a user visits a webpage or opens an email. Because it is so small, it can hardly be seen by visitors of a website or email recipients. These tracking pixels are partly or fully designed to be transparent, or camouflaged in the background color of the website so that they don't stand out to users. Users are usually not supposed to see the tracking pixel. The focus is mainly on the processes that are initiated by downloading the tracking pixel.

Tracking pixels within the source code might look like this:

<img style="“position: absolute;" src="“Tracking">
<img style="“display: none”;" src="“Tracking">
<img src="“Tracking" width="“0”" height="“0”">

The tracking pixel URL is the memory location on the server. When the user visits a website, the image with the tag is loaded from this server. Optical properties such as visibility, or a very small size are defined using the style attribute.