Apple Mail Privacy Protection (MPP)

Apple Mail Privacy Protection (MPP) is a privacy feature in Apple Mail that preloads email content through Apple proxy servers and hides the reader's IP address. Because the tracking pixel loads whether or not the person reads the message, MPP makes open rates unreliable for Apple Mail recipients.

What is Apple Mail Privacy Protection?

Apple introduced MPP with iOS 15, iPadOS 15, and macOS Monterey in September 2021. When users open the Mail app they are asked whether to "Protect Mail Activity," and most say yes. It applies to any account read through Apple Mail, including Gmail and work addresses, but not to the Gmail app or Outlook app on the same phone.

How MPP works

With MPP on, Apple downloads a message's remote content, including the invisible tracking pixel that normally signals an open, through its own proxy servers, often shortly after delivery. The sender sees a pixel load from an Apple IP at an Apple-chosen time. That breaks three things: open tracking, IP-based geolocation, and open-time data for Apple Mail readers.

How MPP affects email metrics

Open rates inflate because pixels fire for unread mail, and Apple Mail typically accounts for a large share of B2C audiences. Anything built on opens inherits the distortion: open-based A/B tests, re-engagement triggers like "has not opened in 90 days," and send-time optimization. Apple Mail opens still have signal for deliverability monitoring, they just cannot be read as human behavior.

What to measure instead

• Clicks and click-through rate, unaffected by MPP

• Conversions: signups, upgrades, and feature adoption from email

• Replies and forwards, the strongest engagement signals email has

• Unsubscribes and spam complaints as the negative baseline

• For re-engagement logic, switch the trigger from opens to clicks or product activity

For the full metric stack, see our guide to email marketing KPIs.

FAQ

Does MPP block all email tracking?
No. It masks opens, open times, and IP-based location for Apple Mail readers. Click tracking, which uses wrapped links rather than pixels, still works.

Do all Apple users have MPP enabled?
Only Apple Mail app users who accepted the prompt, which is the large majority. Reading the same mailbox through the Gmail or Outlook app is unaffected.

Should I stop measuring open rates because of MPP?
Keep opens as a rough deliverability signal, segment them by mailbox provider, and move goals and automation triggers to clicks and conversions.

Related: Open rate, Click-through rate (CTR), Engagement, Newsletter open rate.