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

Key findings

• Encoding method: Apple Private Relay encodes the original sender's email address within the local part of the From: address that the recipient sees.
• Visibility of sender name: The sender's From: name (e.g., Suped Team) is still displayed to the recipient, even when a private relay address is used.
• Domain whitelisting for delivery: For emails to reach @privaterelay.appleid.com addresses, your sending domain must be explicitly whitelisted by Apple.
• Impact of non-whitelisting: If your domain is not whitelisted, emails sent to these addresses will likely bounce, as you lack legitimate access to the underlying real email address.
• ESP role in custom return paths: Your Email Service Provider (ESP) needs to support custom return paths for proper handling of emails to Apple Private Relay addresses.

Key considerations

• Whitelisting process: The responsibility for whitelisting typically falls to your Apple app developers or whoever manages your Apple Developer account. More information can be found on Apple's official documentation.
• ESP compatibility: Ensure your ESP is configured to handle privaterelay.appleid.com addresses correctly. A lack of support may lead to deliverability issues even with proper whitelisting.
• Deliverability strategy: Integrating Apple Private Relay into your email strategy requires attention to Apple's email requirements and understanding its deliverability impacts.
• Bounce management: Monitor bounce rates for these addresses carefully. High bounces might indicate a lack of whitelisting or improper configuration.

Key opinions

• Identity concerns: Marketers are keen to confirm if their 'From' name remains visible to recipients when using Apple Private Relay, as brand recognition is vital.
• Technical transparency: There's a common query about whether the actual email ID is exposed if the Mail Transfer Agent (MTA) or ESP does not fully support Private Relay.
• ESP role confusion: Some marketers report that their ESPs claim not to support Apple Private Relay, leading to confusion about how to proceed and if this affects them negatively.
• Sending domain practices: Many marketers send from their own domains via ESPs, and they need assurance that this setup is compatible with Apple's privacy measures.

Key considerations

• Marketing to Private Relay addresses: While technically possible, sending marketing emails to privaterelay.appleid.com addresses isn't always recommended due to Apple's filtering mechanisms, as highlighted by DailyStory.
• Privacy mask: Marketers should understand that Private Relay masks real email addresses for privacy, requiring adaptation in how they track and manage recipients, as Maileroo Blog explains. Learn more about handling these addresses in email marketing.
• Deliverability optimization: Optimizing for deliverability, particularly with new privacy features, is a continuous process that requires a deep dive into email best practices to ensure messages reach the inbox, impacting overall email deliverability success.

Key opinions

• Sender address encoding: Experts confirm that the sender's original email address is indeed encoded within the local part of the From: address visible to the user, ensuring privacy without complete anonymity.
• Domain whitelisting is essential: A key consensus among experts is the absolute necessity for the sending domain to be whitelisted by Apple for successful email delivery to Private Relay addresses. This is a non-negotiable step.
• ESP capabilities: Experts note that ESPs must support custom return paths for senders utilizing Apple Private Relay, as this is a crucial technical requirement for proper message routing.
• Bounce implications: Lack of Apple whitelisting will result in emails to Private Relay addresses bouncing, signaling that the sender has no legitimate access to the underlying real email address.

Key considerations

• Authentication standards: While not directly about encoding, experts from SpamResource emphasize that robust email authentication (SPF, DKIM, DMARC) remains critical for trust with services like Private Relay.
• List hygiene: Experts at Word to the Wise highlight that new privacy features necessitate stricter list hygiene and engagement practices to maintain good sender reputation, especially to avoid suspected spam issues with Apple.
• Addressing bounces: If emails are bouncing from privaterelay.appleid.com, the primary remediation step is to ensure your domain is correctly whitelisted with Apple and that your ESP properly supports custom return paths.

Key findings

• Randomized addresses: Documentation confirms that Apple Private Relay assigns randomly generated email addresses to users to protect their actual email addresses.
• Email forwarding: These relay addresses forward emails to the user's real email inbox, acting as an intermediary layer of privacy.
• Domain configuration required: Senders must configure their domains to use the Private Email Relay service through their Apple Developer account.
• App capabilities setup: The process involves setting up Sign in with Apple capabilities and adding specific email sources within the Apple Developer portal.
• Compliance with standards: Implied is the need for general email authentication standards (SPF, DKIM, DMARC) to be in place for successful delivery to Apple domains.

Key considerations

• Service setup: Documentation explicitly details the steps for configuring the Private Email Relay service within your Apple Developer account.
• Domain verification: Senders must ensure their domains are verified and associated with their Apple Developer account to allow emails to be relayed to user inboxes.
• Handling bounces: Documentation, implicitly and explicitly, suggests that unverified or non-whitelisted domains will experience email bounces. Understanding causes of transformation errors is key.
• Email authentication: While not solely about Private Relay, the foundational importance of authentication (SPF, DKIM, DMARC) is continuously stressed in documentation for general deliverability, including to Apple domains. For further information, see our guide on a simple guide to DMARC, SPF, and DKIM.