When Apple launched Mail Privacy Protection (MPP) in iOS 15, it sent shockwaves through the email marketing industry. Open rates — long the default metric for email engagement — became unreliable overnight for a significant portion of audiences. If you're using SFMC and haven't yet assessed how MPP is affecting your reporting, this post walks you through how to do it.
What Apple Mail Privacy Protection Does
MPP works by pre-fetching email content — including tracking pixels — through Apple's proxy servers when an email is delivered, regardless of whether the subscriber actually opens it. This means that every email delivered to an Apple Mail user on an MPP-enabled device registers as an 'open' in your ESP's tracking, even if the subscriber never looked at it. The result: artificially inflated open rates that no longer reflect actual human engagement.
How to Identify MPP Opens in SFMC
SFMC's tracking data includes user agent information that can help you identify MPP-triggered opens. Specifically, opens originating from Apple's proxy servers often show a user agent string containing 'Apple Mail Privacy Protection' or originate from Apple's IP ranges. You can query the _Open system data view and filter for these user agents to get a count of likely MPP opens versus genuine human opens. This won't be perfectly precise, but it gives you a reasonable estimate.
Calculating Your MPP Exposure
Run a SQL query against your _Open data view for a representative time period — ideally 30 to 90 days of recent sends. Group opens by user agent and calculate what percentage of your total opens are coming from Apple proxy sources. If 40% of your opens are MPP-triggered, your 'real' open rate is significantly lower than what your dashboard shows. This percentage is your MPP exposure rate, and it's the key number for understanding how much your open rate metrics have been inflated.
Adjusting Your Reporting
Once you know your MPP exposure rate, you can apply it as a correction factor to your historical open rate data. More importantly, going forward, consider reporting on 'adjusted open rate' — total opens minus estimated MPP opens, divided by delivered. Some teams create a separate data extension that logs only non-MPP opens and use that for their primary engagement reporting. This gives you a cleaner signal for measuring actual subscriber engagement.
Shifting to Click-Based Engagement Metrics
The most durable response to MPP is to shift your primary engagement metric from opens to clicks. Click-through rate is not affected by MPP — a click requires a human to actually interact with the email. Rebuild your engagement scoring, re-engagement thresholds, and send frequency logic around click behavior rather than open behavior. This is a more meaningful signal anyway: a subscriber who clicks is demonstrably more engaged than one who merely opens.
Re-Engagement Campaigns in a Post-MPP World
Re-engagement campaigns traditionally targeted subscribers who hadn't opened in a defined period. In a post-MPP world, 'no opens' is no longer a reliable signal of disengagement — an Apple Mail user might be opening every email but registering as a non-opener in your system, or registering as an opener without actually reading. Redesign your re-engagement criteria around clicks and conversions. Subscribers who haven't clicked in 6 months are a much more reliable signal of disengagement than those who haven't 'opened.'
Need Help Adapting Your SFMC Reporting?
MPP changed the rules for email measurement. Light Your Fires can help you audit your current reporting, quantify your MPP exposure, and rebuild your engagement metrics on a foundation that actually reflects subscriber behavior.
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