Glossary

Tracking pixel

A tracking pixel is a small piece of browser-side code — historically a 1×1 image, today usually a JavaScript snippet — placed on a confirmation page to report that a conversion happened. When the page loads, the pixel requests the tracker's server, which records the conversion against the visitor's click.

Strengths and weaknesses

Pixels are trivial to deploy: paste a snippet into the thank-you page and tracking works. That simplicity made them the default for years. But they run in an environment the advertiser does not control — ad blockers strip them, Safari and Firefox limit the cookies they rely on, consent banners delay them, and a closed tab loses them entirely.

Postback (server-to-server) tracking replaces the browser hop with a direct server call carrying the click ID, which is why performance marketing has largely moved to it. Pixels remain common where the counting stakes are lower or where the platform (a social network, a search engine) requires its own pixel.

Related terms