The iOS 14 update did real damage to Facebook’s advertising ecosystem, and event match rates were one of the clearest places you could see it. In this post, I’ll go through what actually happened and the strategies that helped in the campaigns I manage.
Understanding Event Match Rates
Event match rates measure the percentage of users who trigger a specific event (a purchase, a newsletter sign-up, a checkout initiation) after clicking on a Facebook ad. High match rates mean your ads are correctly tracking the actions they’re supposed to drive.
iOS 14 broke a meaningful chunk of that tracking. Apple’s App Tracking Transparency framework required user consent for apps to track activity across other apps and websites. A large percentage of users don’t consent. That opt-out rate effectively limited Facebook’s visibility into what users did after clicking an ad, which in turn limited the platform’s ability to optimize for conversions.
Strategies for Improving Event Match Rates
The technical fixes matter most here. The general campaign hygiene items further down are real, but they’re not specific to the match rate problem - start with these:
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Verify your domain. Domain verification in Meta Business Manager establishes ownership and is a prerequisite for prioritizing conversion events. If you haven’t done this, it’s the first step before anything else.
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Implement Aggregated Event Measurement. Facebook now limits the number of conversion events you can track per domain. Prioritize your most important events (purchases, leads, whatever you’re actually optimizing toward) and consider combining similar ones (like “Add to Cart” and “Initiate Checkout”) if you’re running tight on the event limit.
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Use the Conversions API. The CAPI is the most impactful fix for match rates. It sends event data directly from your server to Facebook’s servers, bypassing the client-side limitations that iOS 14 introduced. Running CAPI alongside your pixel (not instead of it) gives Facebook more signal to work with, especially for users who’ve opted out of tracking.
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Lean on first-party data. Data you collect directly through your website or app (email addresses, phone numbers, customer lists) is less dependent on third-party tracking. Feeding that back into Facebook via custom audiences improves targeting and match quality.
The remaining items are good campaign practice regardless of match rates: segment your audiences around actual behavior and demographics, test ad creative and formats systematically, make sure your landing page delivers what the ad promises, and be transparent with users about data tracking when the ATT prompt appears. These won’t fix a broken pixel or a missing CAPI setup, but they do affect whether optimized campaigns perform once the tracking signal is healthy.
Conclusion
iOS 14 narrowed the data Facebook campaigns run on, and there’s no single fix that fully restores what was there before. The CAPI implementation and domain verification are the highest-leverage technical moves. First-party data investment is the longer-term answer. The rest is ongoing optimization work that should be running anyway.