Definition:
A tracking pixel is a resource used to record a page load or an action performed on a website. Traditionally, it could be a transparent one-pixel image requested from a server; in current usage, the term is also applied to tags and code snippets that send events to an analytics or advertising platform.
Depending on its configuration, it may communicate data such as the page visited, the time of the request, the browser type, the referrer or identifiers associated with a campaign. It may also record actions defined with JavaScript, such as a form submission or purchase. Its use must comply with applicable permissions, consent requirements and data protection rules.
These pixels are used to measure campaign performance, attribute conversions and create audiences based on observed actions. The information available depends on the implementation, browser settings and privacy restrictions; installing a pixel does not by itself guarantee complete measurement.
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Types of pixels
Depending on the measurement objective, pixels are mainly used for remarketing and conversion tracking:
Remarketing pixels: record visits or actions to build audiences that may later be used in remarketing campaigns. Whether a person is included in an audience depends on the configured rules and on having a valid basis for processing the data.
Conversion pixels: record actions considered valuable, such as a purchase, registration or contact request. They can connect these events with an advertising campaign when the platform has the information needed to attribute them.
What are the most common pixels?
Platforms use different names, and not all of them call their technology a pixel. Well-known advertising tags include:
- Meta Pixel, formerly called Facebook Pixel.
- Google tag, the current name of the tag used by Google Ads for conversion measurement.
- AdRoll Pixel.
- Microsoft Advertising UET tag, previously commonly associated with Bing Ads.
- X Pixel, for the platform formerly called Twitter.
These solutions may combine a base tag with specific events and, in some cases, server-side measurement. Their names, functions and configuration requirements can change, so the current documentation for each platform should be used.