How Apple’s ‘Mail Privacy Protection’ changed email marketing

Email Marketing Article
20 mins

These are complicated times for digital marketers. On one hand, marketing technology keeps giving us better ways to finetune campaigns to the individuals in our audiences. On the other hand, tech companies and regulators are putting up new obstacles to our ability to gather accurate customer data and deliver personalised marketing – usually in the name of user privacy.

This article looks at a particularly serious challenge for email marketers that first reared its head in 2021: Apple’s implementation of ‘Mail Privacy Protection’ for the Apple Mail email client.

We’ll take you through how Mail Privacy Protection works, some of the ways it affects tracking pixels and related technologies, and how you can adapt your methods for continued email marketing success, despite losing some audience insight.


What is Apple ‘Mail Privacy Protection’?


Mail Privacy Protection (MPP) is a security option for Apple Mail users. When the option is active, Apple Mail blocks features of emails that attempt to provide information about the recipient to the sender, especially tracking pixels.

Apple introduced MPP, along with other security features including an app privacy report for iOS users, in 2021.



Apple Mail users can turn MPP on or off using an option in the application’s settings. When a user changes their MPP setting on one device, the change is carried through to other devices associated with the same Apple ID – so if a person turns on MPP using their iPhone’s Apple Mail app, the change could carry through to their MacBook, for example.

New Apple Mail users are given a prompt to choose whether they want to activate MPP the first time they open Apple Mail, in the form of a selection between “Protect Mail activity” and “Don’t protect Mail activity”. Given how Apple Mail phrases this question, there’s a convincing argument for many users to opt-in to MPP.


What does Mail Privacy Protection actually block?


Tracking and measurement of email marketing is often done using ‘tracking pixels’, which work roughly as follows:

  • A tiny, unnoticeable, one-pixel ‘image’ is added to each recipient’s email, in the header, footer or body.
  • When a recipient opens an email, this causes the pixel to load a tracking pixel’s image file from a web URL that’s unique to the email and the recipient.
  • The sender’s email marketing platform can see that the recipient’s unique URL has been used to load a pixel, so it can deduce that the recipient has interacted with the email in a certain way, e.g. opened the email.
  • The sender can look at their email marketing analytics and see which recipients opened an email.

As well as tracking when an email is opened, tracking pixels can tell marketers things like the recipient’s IP address and geo-location, the device type(s) they used, and how many times they opened the email.

These are the sorts of pixel-powered tracking that MPP can block. 


How Mail Privacy Protection works


Here’s a very simple breakdown of roughly how MPP works in Apple Mail:

  1. The user’s Apple Mail account receives an email.
  2. Before the user can open the email, the app downloads the email content. If the email contains images (including what could be tracking pixels), the app makes copies of them and stores the copies in a private cache.
  3. If the user subsequently opens the email, any images they see are copies of the originals, downloaded from Apple Mail’s private cache. (Normally, the images would be loaded from the sender’s chosen online source, which is crucial to their use in tracking.)

In a nutshell, when MPP is active, Apple Mail replaces all the images featured in an email with identical copies that can’t be used by the sender to gather data about the recipient.

If you’re interested in the technical detail of how MPP works, you can find a more in-depth description via email expert Litmus.


How the loss of email tracking capability affects marketers


The most infamous impact of MPP on email marketing is loss of accuracy in email campaign analysis. Since the implementation of MPP, marketers have reported distorted results for metrics including:

  • Open rates (unique opens AND total opens)
  • Recipient geo-location
  • Clicks per unique open
  • Recipient email client

Furthermore, not only are tracking pixels and similar mechanisms used to measure the outcomes of email campaigns; they can also play an important role in triggering actions in automated marketing.

For example, a sales exec might set up an automation so that when an activated tracking pixel shows that a recipient has opened an email, a follow-up email is automatically scheduled for that recipient.

By blocking the use of tracking pixels, Mail Privacy Protection denies marketers the benefits of all these uses and more. Every inbox equipped with Mail Privacy Protection degrades marketers’ ability to learn things about their audience and personalise campaigns for individuals.

MPP can adversely affect any email marketing activity that relies on accurate tracking of email opens, including A/B tests that use measurement of open rates to help marketers identify optimal campaign tactics, such as the best time of day to send an email, or the best email subject line to use.


How Mail Privacy Protection has affected open rates


Without a doubt, the most infamous impact of MPP has been its inflationary effect on the reporting of email campaign open rates.

With MPP, Apple Mail opens each email sent to a user before the person can open/ignore/delete that email. When Apple Mail opens the email, this causes the images within the email – including tracking pixels – to be ‘opened’ from the sender’s URL. The outcome is that the sender’s analytics registers that the pixel has been accessed, and therefore logs the email as opened in the campaign data.

Post-MPP, different observers have made contrasting statements about MPP’s effect on open rates. In a 2022 survey of email marketers by GetApp, 30% of marketers said their open rates had been inflated by MPP. That may seem like a low percentage, but we should take into account that MPP is still relatively new and unfamiliar. As more marketers learn about the Apple Mail feature, they may be likelier to recognise its effects on campaign data.

A large-scale study by Omeda, published March 2022, shows that MPP has pushed up open rates across the industry. Omeda analysed ~80,000 email marketing accounts, which sent ~two billion emails during the period observed, to see how their open rates had changed within three months, and then six months, of MPP’s launch.

The key findings from Omeda’s analysis were as follows:



Before MPP

After MPP

Emails sent period

19 May to 18 July 2021

19 July to 17 August 2021

27 Aug to 26 Nov 2021

27 Nov 2021 to 26 Jan 2022

2 Jan to 3 March 2022

Total Open Rate






Unique Open Rate






Source: The Impact of Apple’s Mail Privacy Protection – 6 Months Later (Omeda)


Simply put, Omeda saw the average open rates for their clients’ emails almost double between the months leading up to MPP’s launch and March 2022.

For email marketers, this effectively rules out open rates as a reliable measure of campaign performance.


Email marketing measurement, post-MPP


MPP has prompted email marketers to adjust their approach to campaign measurement.

Rather than focusing on big-picture reporting of “glamour metrics” like open rate, there’s now a greater focus on tracking goal-related events such as clicks-through and conversions.

This mirrors developments in web and app analytics, e.g. the reorientation of Google Analytics towards event tracking that has come to fruition in the platform’s most recent iteration, GA4. Across many key digital mediums, privacy updates are marginalising tracking tech like cookies and tracking pixels – leading marketers, and industry players like Google, to reorient their approach to measurement.

Each email campaign will benefit from a bespoke measurement mix. With that said, we can recommend the following tactics for email measurement and personalisation, post-MPP:

  • Make clicks and conversions the focus of measurement. For many years, there’s been a school of thought in email marketing that says the most important metrics to track are conversion-related ones, such as total clicks and clicks-through leading to on-website conversions. The impact of MPP has given email marketers another reason to adopt a conversions-first approach to measurement – which is the type of approach we argue for in our guide to email marketing best practice.
  • Monitor bounces and unsubscribes. Whereas clicks and conversions will help you to measure good outcomes of email campaigns, a campaign’s bounce rate and unsubscribe rate will provide insight into what’s not working as it should.
  • Set up alternative ways to identify customer geo-location. Where a customer is based can greatly affect their wants, needs and likely behaviours. Post-MPP, email tracking is not reliable for identifying where someone is located. So, if we are to use location as a factor in marketing campaigns, we need to use other methods of attributing a location to each customer. Effective ways to do this include sign-up forms and customer surveys.

The common thread among the changes to email marketing caused by MPP is that we can now safely say that it’s better to track customer metrics in the moments when a customer knowingly interacts with your brand, rather than when they interact with a third-party application, i.e. the inbox in their email client.

Arguably, this was the best approach all along – it might just take some time for brands and email marketers to adapt their methods and see the upsides of this new way of doing things.


What proportion of email activity is affected by MPP?


Part of the reason MPP matters so much is Apple Mail’s dominant position in the email client market.

According to Litmus, Apple Mail had a market share of 58% in May 2022, which puts it at a massive advantage over the second and third most popular email clients, Gmail (28.1%) and Outlook (4.2%).

The upshot of Apple Mail’s popularity is that well over half of your mailing list could have the option of using MPP. We can’t say for sure what proportion of people using Apple Mail will have MPP active, but based on how attractively Apple Mail presents the setting to new app users, it seems very likely that uptake of MPP will be high.

For the average brand, most of your mailing list will be using Apple Mail – and a high proportion of those people are probably using MPP too.


Why Mail Privacy Protection is an opportunity for better email marketing


There’s no doubt that Apple Mail’s implementation of Mail Privacy Protection has caused a lot of disruption and made a lot of work for email marketers. Across a huge swathe of email accounts, the new feature has made it harder to gain insights into audience members and personalise their experiences.

With all that said, you could also view MPP as an opportunity to refresh your approach to email marketing. Traditional tracking has become less reliable – which would make this a smart moment to implement or fine-tune alternative tactics such as conversion tracking or personal information collection via customer surveys.

MPP will likely affect your brand similarly to how it affects your close competitors, which probably have similar customers with comparable email client preferences. The real difference-maker will be which brands adapt to post-MPP email marketing most effectively.

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