An Engagement Custom Audience is built from users who have previously interacted with a brand’s content on Meta platforms,, including video views, Instagram profile visits, Facebook Page interactions, lead form opens, or event responses. Unlike website-based Custom Audiences, engagement audiences don’t require a Pixel and are built entirely from on-platform activity. They are particularly effective for warming up cold audiences before directing users to a landing page, or retargeting users who showed interest but never converted. Engagement audiences are one of the most cost-effective retargeting pools available on Meta for advertisers with limited pixel data.