How does Apple Private Relay encode email addresses and how does domain whitelisting affect deliverability?

Summary

Apple Private Relay impacts email deliverability through email address encoding and the necessity of domain whitelisting. Email addresses are encoded in the local part of the 'From:' or recipient address. Domain whitelisting is essential for deliverability; failure to comply results in bounces. Additionally, managing sender reputation, implementing email authentication (SPF, DKIM, DMARC), monitoring feedback loops, maintaining clean lists, and properly configuring the Private Email Relay service are crucial.

Key findings

  • Address Encoding: Email addresses are encoded either in the 'From:' address or in the local-part of the @privaterelay.appleid.com recipient address.
  • Whitelisting Requirement: Apple requires domain whitelisting for senders to deliver emails to private relay addresses.
  • Bounce Risk: Without whitelisting, emails bounce, and senders have no legitimate access to the addresses.
  • Reputation Impact: Private Relay masks user behavior, potentially leading to deliverability issues and impacting sender reputation if not managed correctly.
  • Authentication Importance: Proper authentication (SPF, DKIM, DMARC) verifies legitimacy and prevents emails from being marked as spam.
  • List Hygiene: Maintaining clean and engaged email lists is crucial due to the masking of user identities.
  • Service Configuration: Configuring the Private Email Relay service is essential for correct routing and deliverability.

Key considerations

  • Domain Whitelisting: Ensure your domain is whitelisted with Apple for sending to private relay addresses.
  • Email Authentication: Implement and maintain SPF, DKIM, and DMARC records.
  • Feedback Loop Monitoring: Monitor feedback loops to address deliverability issues arising from spam complaints.
  • List Management: Practice good list hygiene, removing inactive or unengaged subscribers.
  • Service Setup: Configure Private Email Relay settings properly, associating domains and enabling app capabilities.
  • Engagement Tracking: Monitor engagement metrics closely and adjust sending strategies as needed.

What email marketers say
6Marketer opinions

Apple Private Relay impacts email deliverability by encoding recipient email addresses, potentially masking user behavior, and requiring domain whitelisting. Improper management can negatively affect sender reputation and list hygiene, emphasizing the need for careful monitoring of engagement metrics and adherence to email authentication best practices.

Key opinions

  • Encoding: Apple Private Relay encodes the original recipient's email address into the local-part of the @privaterelay.appleid.com address, requiring senders to handle these addresses correctly.
  • Reputation Impact: Using Private Relay can impact sender reputation due to masked user behavior and potential spam reports from recipients.
  • Deliverability Complications: Private Relay complicates deliverability by masking user identities and affecting list hygiene, necessitating close monitoring of engagement metrics.
  • Whitelisting Importance: Domain whitelisting is essential as Apple requires senders to be verified to prevent abuse, with failure to do so resulting in bounced emails and negative impact on sender reputation.

Key considerations

  • Authentication: Maintain a clean sending reputation, authenticate emails using SPF, DKIM, and DMARC, and monitor bounce rates.
  • Engagement Monitoring: Monitor engagement metrics closely and adjust sending strategies accordingly to mitigate deliverability issues.
  • Clean Lists: Maintain clean and engaged email lists, avoiding sending to inactive or unengaged relayed addresses.
  • Handling Relayed Addresses: Ensure your systems can properly handle and parse the @privaterelay.appleid.com addresses to avoid routing errors.
Marketer view

Email marketer from Litmus explains that domain whitelisting is essential when sending emails to Apple Private Relay addresses because Apple requires senders to be verified to prevent abuse. Failure to whitelist can result in bounced emails and negatively impact sender reputation.

February 2024 - Litmus
Marketer view

Email marketer from EmailToolTester shares that Apple’s Private Relay can complicate email deliverability because it masks user identities and can affect list hygiene. They recommend monitoring engagement metrics closely and adjusting sending strategies accordingly.

August 2023 - EmailToolTester
Marketer view

Email marketer from Reddit shares that using Apple's Private Relay can impact sender reputation if not managed correctly, as the relayed addresses can mask user behavior and potentially lead to deliverability issues if recipients mark emails as spam.

February 2025 - Reddit
Marketer view

Email marketer from Mailjet outlines that to ensure successful delivery to Apple Private Relay addresses, it is crucial to maintain a clean sending reputation, authenticate your emails using SPF, DKIM, and DMARC, and monitor bounce rates to promptly address any deliverability issues.

November 2021 - Mailjet
Marketer view

Email marketer from SendGrid explains that Apple Private Relay can impact email marketing metrics by providing users with the ability to mask their real email addresses and that domain whitelisting is necessary for proper deliverability.

January 2025 - SendGrid
Marketer view

Email marketer from StackOverflow explains that Apple Private Relay encodes the original recipient's email into the local-part of the @privaterelay.appleid.com address. Senders need to handle these addresses correctly to avoid parsing or routing errors.

February 2025 - StackOverflow

What the experts say
6Expert opinions

Apple Private Relay impacts email deliverability by encoding the sender's email address and requiring domain whitelisting. Encoding places the sender's email in the local part of the 'From:' address. Domain whitelisting by Apple is necessary to send to private relay addresses; failure to whitelist results in bounced emails. Proper authentication (SPF, DKIM, DMARC), monitoring of feedback loops, and maintaining clean email lists are crucial for deliverability.

Key opinions

  • Email Encoding: The sender's email address is encoded in the local part of the 'From:' address when using Apple Private Relay.
  • Whitelisting Requirement: Sending domains must be whitelisted by Apple to ensure deliverability to private relay addresses.
  • Bounce Risk: If a domain is not whitelisted by Apple, emails will bounce and access to the email addresses is illegitimate.
  • Authentication Importance: Proper authentication using SPF, DKIM, and DMARC is crucial for verifying the legitimacy of emails and preventing them from being flagged as spam.
  • Feedback Loops: Monitoring feedback loops is important for identifying and addressing deliverability issues arising from users marking emails as spam.
  • List Hygiene: Maintaining clean and engaged email lists is critical; sending to inactive or unengaged relayed addresses can negatively impact sender reputation.

Key considerations

  • Domain Whitelisting: Ensure your sending domain is properly whitelisted with Apple to send to private relay addresses.
  • Authentication Setup: Implement and maintain SPF, DKIM, and DMARC for your sending domains.
  • Feedback Loop Monitoring: Regularly monitor feedback loops to identify and address deliverability issues.
  • List Management: Maintain clean and engaged email lists by removing inactive or unengaged subscribers.
Expert view

Expert from Email Geeks explains that the email address you send from is encoded in the local part of the From: address as the user sees it.

June 2022 - Email Geeks
Expert view

Expert from Email Geeks shares that your sending domain needs to be whitelisted by Apple to send to private relay addresses. Assuming you’re whitelisted with Apple, it should work fine if your ESP can provide custom return paths and your domain is in there.

March 2022 - Email Geeks
Expert view

Expert from Spam Resource highlights the importance of monitoring feedback loops when sending to Apple Private Relay addresses. This allows senders to identify and address any deliverability issues that may arise due to users marking emails as spam.

July 2021 - Spam Resource
Expert view

Expert from Spam Resource advises that with Apple Private Relay, maintaining clean and engaged email lists is crucial. Sending to inactive or unengaged relayed addresses can negatively impact sender reputation and deliverability.

May 2023 - Spam Resource
Expert view

Expert from Email Geeks explains that if you’re not whitelisted with Apple, the mail will all bounce, and you also have no legitimate access to the email addresses.

June 2024 - Email Geeks
Expert view

Expert from Spam Resource explains that to ensure email deliverability with Apple Private Relay, senders must properly authenticate their sending domains using SPF, DKIM, and DMARC. This helps to verify the legitimacy of the email and prevents it from being flagged as spam.

July 2023 - Spam Resource

What the documentation says
3Technical articles

Apple's documentation outlines the necessity of configuring the Private Email Relay service for proper email deliverability. This involves setting up an associated domain, enabling the capability within the app's settings in App Store Connect, and understanding that Hide My Email generates unique @privaterelay.appleid.com addresses that require proper domain whitelisting.

Key findings

  • Service Configuration: Properly sending emails using Apple Private Relay requires configuring the Private Email Relay service.
  • Domain Association: Setting up an associated domain is a crucial step in configuring the Private Email Relay service.
  • App Capability: Enabling the Private Email Relay capability within the app's settings in App Store Connect is required.
  • Unique Addresses: Hide My Email generates unique, random email addresses ending in @privaterelay.appleid.com.
  • Whitelisting Requirement: Sending to @privaterelay.appleid.com addresses requires proper domain whitelisting.

Key considerations

  • App Setup: Ensure the Private Email Relay capability is correctly configured within your app's settings.
  • Domain Verification: Set up and verify an associated domain for use with the Private Email Relay service.
  • Deliverability Best Practices: Implement domain whitelisting and follow deliverability best practices to ensure emails reach intended recipients using Private Relay.
Technical article

Documentation from Apple Support describes that Hide My Email allows users to create unique, random email addresses that forward to their personal inbox, and these addresses are in the @privaterelay.appleid.com domain. Sending to these addresses requires proper domain whitelisting to ensure deliverability.

November 2024 - Apple Support
Technical article

Documentation from Apple details that to properly send emails to users utilizing Private Email Relay, developers must configure their app capabilities, specifically the Private Email Relay service, to ensure correct routing and deliverability.

April 2023 - Apple Developer
Technical article

Documentation from Apple Developer explains how to configure the Private Email Relay service, which involves setting up an associated domain and enabling the capability within the app's settings in App Store Connect.

October 2023 - Apple Developer Documentation

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