How does MPP affect open rates and engagement data?
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Since Apple rolled out Mail Privacy Protection (MPP) in 2021, open rates have become genuinely tricky to trust. Here's the short version of why: Apple Mail pre-fetches tracking pixels before a subscriber even looks at your email. That pixel fires, your ESP records an open, and nobody actually read a word.
The scale of this matters. If a big chunk of your list uses Apple Mail on iPhone, iPad, or Mac, you could be seeing 20 to 40 percentage points of phantom opens baked into your numbers. A reported 55% open rate might be 30% real opens plus 25% MPP pre-fetches. You can't tell which is which just by looking at the number.
What you can do is stop leaning on opens as your primary engagement signal. Clicks, purchases, replies, form fills, these all require a real human to make a deliberate choice. MPP can't fake a click. So if your click-to-open rate suddenly looks low after MPP took hold, that's actually the honest signal trying to get through the noise.
A few practical moves worth making:
- Shift your engagement benchmarks to clicks and conversions. Opens are still useful as a rough directional signal (a total collapse in opens is still worth investigating), but don't use them for subscriber-level decisions.
- Segment by device or email client if your ESP supports it. Some platforms can tag Apple Mail openers separately so you're not mixing MPP-inflated numbers with real engagement data from Gmail or Outlook users.
- Rethink your sunset policy. If you're sunsetting subscribers based on "hasn't opened in 90 days," MPP can mask genuinely disengaged people as active. Use click-based inactivity windows instead (or both, with different thresholds).
- Look at downstream behavior. Website visits from email links, coupon redemptions, login events triggered by your email, these are all more honest than a pixel fire.
The silver lining here (if there is one) is that MPP pushed a lot of senders toward metrics that actually matter. Clicks and conversions were always better engagement proxies. MPP just made ignoring that harder.
If you want to understand what MPP actually does under the hood, that's a good place to start before you reconfigure your reporting. And if you're not sure how your current engagement data stacks up, our SOS hotline is free, no pitch, just a straight answer.
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