Measurement pixel

A short piece of code, also called a tracking pixel, that an advertising platform gives an advertiser and that reports what visitors do on the advertiser's website back to the platform. The advertiser places the code on the site, and the code runs in each visitor's browser. Each report records a page view or an action the advertiser counts as a result, such as a purchase. The platform links the reports to the ads the visitors saw or clicked, so the advertiser learns which ads led to results. Because the code runs in the browser, ad blockers and browser privacy settings stop part of its reports. In the European Economic Area, the law requires the visitor's consent before the code runs. A Conversions API, where API stands for application programming interface, sends reports of the same kind from the advertiser's own systems, outside the browser. Some platforms supply the code with consent switched on, so a site serving visitors from the European Economic Area has to hold it back until each visitor agrees.