How does a tracking pixel work

The website operator or sender of an email adds the tracking pixel using a code in the website’s HTML code or email. This code contains an external link to the pixel server. If a user visits the destination website, the HTML code is processed by the client – usually the user’s browser. The browser follows the link and opens the (invisible) graphic. This is registered and noted in the server’s log files.

In addition, various information about the user is also transmitted using this method. To some extent, combination with JavaScript is necessary in order to collect information about the operating system or browser type.

The following data can be acquired and analyzed with a tracking pixel.

- Operating system used (gives information on the use of mobile devices)
- Type of website or email used, for example on mobile or desktop
- Type of client used, for example a browser or mail program.
- Client’s screen resolution
- Time the email was read or website was visited
- Activities on the website during a session (when using multiple tracking pixels)
- IP address (gives information on the Internet Service Provider and location)

Inserting a tracking pixel
Depending on the system, the installation of a tracking pixel differs. Sometimes this can be done via the content management system used, sometimes the pixel must be implemented directly in the source code of the e-mail or website.

The web analysis tools that require the implementation of the pixel, such as Facebook or Google Analytics, offer extensive implementation instructions.