What is a Facebook pixel?A Facebook pixel is an analytics tool that consists of a code that you can put on your website. The pixel fires to track site visitors. This data allows you to retarget those users with Facebook ads in the future, as well as see what they’re doing on your site when they return. This allows you to gain more insights about your audience, send targeted messaging to users who already know your brand, and track the effectiveness of your paid social advertising efforts.How do Facebook pixels work?Facebook used to have a custom audience pixel for retargeting website visitors, and conversion pixels for tracking website conversions such as sales. While each advertising account had only one custom audience pixel, you could create many conversion pixels — one for each web page you wanted to track conversions on.