iOS, ATT, and Your Meta Tracking: What Actually Changed

Apple's App Tracking Transparency (ATT) reshaped how Meta ads are tracked and attributed. The details are technical, but the practical takeaways for media buyers are simple. Here's what changed and what to do about it.

What ATT actually did

Starting with iOS 14.5, apps have to ask users for permission before tracking them across other apps and websites. Most users decline. For Meta, that means a large share of iOS users can no longer be tracked the old way, which reduced the signal Meta receives from browser-based tracking.

The downstream effects

• Under-reported conversions.Some conversions from opted-out users simply don't get attributed, so your in-platform numbers can look lower than reality.
• Delayed and modeled data. Meta now relies more on modeled and aggregated measurement, which can mean slower or estimated reporting.
• Smaller, slower audiences. Retargeting pools built purely from browser signals shrank.

What to do about it today

• Run the Conversions API.Server-side events aren't subject to the same browser restrictions, so CAPI recovers a meaningful share of the signal ATT took away. If you only take one action, this is it. See Pixel vs CAPI.
• Maximize Event Match Quality. Send rich, hashed customer parameters so Meta can match the events you do send. See what makes a good EMQ score.
• Verify your domains and prioritize events in Events Manager so your most important conversions are measured under the aggregated model.
• Judge performance on blended metrics.Compare Meta's numbers against your own backend data rather than trusting in-platform reporting alone.

The new baseline: protect the signal you have

In a post-ATT world, every bit of tracking signal counts more — so a broken pixel or a CAPI setup that quietly stops sending match keys is more costly than ever. Taglert monitors your pixel activity, EMQ, and duplicate rate continuously and alerts you the moment your signal degrades, so you protect the data you fought to keep.