Apple's introduction of App Tracking Transparency (ATT) on April 26, 2021, significantly impacts the advertising ecosystem by requiring iPhone and iPad users to opt-in for apps to track them across websites, leading to greater user privacy but potentially reducing ad performance. The update restricts access to the Identifier for Advertisers (IDFA), a crucial tool for platforms like Facebook to track and retarget users, affecting conversion data, retargeting audiences, and lookalike audience performance. With iOS devices accounting for a major share of mobile devices, advertisers face challenges in data tracking and attribution due to blocked third-party cookies, limiting Facebook's ability to optimize ad delivery. Clearbit Conversions offers a solution by using server-side conversion tracking methods, bypassing cookie-blocking technologies, and enhancing data accuracy without relying on traditional cookies, thus protecting and potentially improving ad performance and lead quality. This system integrates with Facebook's Conversions API and Google's Offline Conversion Tracking to maintain effective targeting by enriching conversion events with critical metadata and improving machine learning capabilities, thus adapting to the changing digital advertising landscape.