Why it exists
After Apple's App Tracking Transparency, Meta cannot measure iOS activity the old way. AEM is the protocol it uses instead for people on iOS 14 and later. Meta says its processing includes removing identifiers, adding differential privacy and aggregating data across users before personalizing ads and measuring how they perform. (Meta Business Help Center)
What changed
AEM used to cap each verified domain at eight conversion events, ranked by priority in an Events Manager tab. Meta has been rolling out a simpler version for website events: you no longer prioritize eight events per domain, you don't need value sets to use value optimization, the AEM tab is gone, domain verification is no longer needed for event configuration, and you don't pick a conversion domain when you build a campaign. Meta says there are no steps you need to take for your events to be processed through AEM.
What still matters
With no ranking step, the lever is signal quality: send the events that reflect real value, like purchase or qualified lead, and send them reliably. That is why server-side tracking and strong event match quality matter more than ever. Meta notes that events sent through the Conversions API may also be processed within AEM's limits, so CAPI improves signal but doesn't take iOS events outside AEM.
Common questions
What is Aggregated Event Measurement?
Meta's protocol for measuring web and app events from people using iOS 14 and later devices. Its processing removes identifiers, adds differential privacy and aggregates data across users before ads are personalized and measured.
Do I still need to rank eight events in Aggregated Event Measurement?
No. Meta removed the eight-event limit per domain and manual event prioritization for website events, along with the AEM tab in Events Manager and the need to turn on value sets for value optimization. Eligible website events are processed automatically, so the work shifts to sending accurate, high-value events through the pixel and Conversions API.
Do I still need to verify my domain for Meta ads?
Not for event configuration. Meta says you aren't required to verify your website domains for purposes related to event configuration, and you don't pick a conversion domain when creating a campaign. It notes you may still need domain verification for other reasons.