What’s Apple’s privacy approach to open tracking (MPP)?

You send a campaign, your open rate jumps to 60%, and you feel great about it. Then someone mentions that a huge chunk of those opens might not be real. That's the reality of Apple Mail Privacy Protection (MPP), which Apple Mail rolled out with iOS 15 in 2021.

Here's what actually happens. When a user has MPP turned on, Apple's proxy servers fetch your email's images, including your open tracking pixel, before the person ever lays eyes on the message. That pixel fires, your platform logs an open, and you have no idea whether the subscriber actually read a single word.

So opens from Apple Mail users get recorded regardless of whether the email was opened, deleted unread, or sitting in a folder untouched. Your reported open rate goes up. Your actual engagement picture goes murky.

There's a real upside for users here, and it's worth saying out loud. MPP means senders can't tell when someone opened, where they were, or what device they used. That's a genuine privacy win. It's just a headache for anyone trying to use opens as a meaningful metric.

The practical shift this forces is away from passive signals (open rates) and toward actions that require an actual human to do something, like clicking a link, making a purchase, or replying to an email. Clicks, conversions, and revenue per email become far more reliable signals of engagement than opens alone. If you're still making send decisions, sunset rules, or segmentation cuts based on open data, you're likely working with inflated numbers that don't reflect real interest.

It's also worth knowing that MPP applies to the Apple Mail app across iPhone, iPad, and Mac. It doesn't affect Gmail's app or other clients, even on Apple devices. So your open data isn't entirely broken, it's just mixed. Some opens are real, some are Apple's servers. You can't tell them apart from a pixel alone.

If you want to understand how MPP skews your engagement numbers in practice, that's worth a read next.