Apple's private email relay, branded Hide My Email, lets a person generate a random alias address that forwards to their real inbox. The sender only ever sees the alias, never the underlying address. It ships with Sign in with Apple and with iCloud+, and it gives users a way to sign up for services without handing over their actual email. For senders, the practical effect is that some of your recipients have addresses you can never see.
How does the relay work?
When a user chooses Hide My Email, Apple mints a unique random address, usually ending in @icloud.com or @privaterelay.appleid.com, and binds it to their account. Mail you send to that alias hits Apple's relay servers, which then forward it on to the user's real inbox. The user reads and replies as normal; your view stops at the alias.
The mapping is one alias per service in most flows, so a user can hand a different address to every site they join. If one of those aliases starts getting unwanted mail, the user can disable it, and from then on your messages to that alias stop being delivered. Nothing about your sending changes; the relay simply stops forwarding.
What does a sender actually see?
You see the relay alias and nothing else. Your contact record stores something like a1b2c3@privaterelay.appleid.com, your analytics attribute opens and clicks to that alias, and your replies route back through the relay. You cannot resolve the alias to a real address, and you should not try to. Treat the alias as the recipient's address for every purpose, because as far as your system is concerned, it is.
What does it mean for deliverability?
Mail to a relay alias still passes through Apple's infrastructure, and Apple enforces sender standards before it forwards anything. Two things matter most:
- Authentication is not optional. Your domain needs valid SPF, DKIM, and DMARC alignment. Relayed mail is scrutinized, and unauthenticated mail is the first thing to get filtered or dropped. If you have not locked down authentication and deliverability fundamentals, relay recipients are where it shows up first.
- Aliases can be disabled. A user can turn off any alias at will. When they do, your mail to it stops delivering. There is nothing to fix on your end; it is the user exercising the control the feature gives them. Watch for aliases that quietly stop engaging and treat them like any other disengaged contact.
Because the relay forwards rather than rewrites the destination, your sending domain and reputation carry through. Good standing helps your relayed mail land; poor standing hurts it just as it would anywhere else.
How is this different from Mail Privacy Protection?
They are two separate Apple features, and it is easy to conflate them. Hide My Email is about the address: it hides the user's real email behind a forwarding alias. Mail Privacy Protection is about tracking: when enabled, Apple Mail pre-fetches remote images (including tracking pixels) so opens register whether or not the user actually read the message. One obscures who the recipient is; the other obscures whether they engaged.
The tracking side is why open rates from Apple Mail clients are unreliable as a precise signal. If opens drive any of your logic, read how to track email opens for what the metric can and cannot tell you under Mail Privacy Protection.
Frequently asked questions
Can I find a user's real email behind the alias?
No, and you should not try. The alias is the address Apple gives you, and the mapping to the real inbox is private by design. Store the alias, send to it, and treat it as the recipient's canonical address.
Will my mail to a relay alias bounce if the user disables it?
Once a user disables an alias, mail to it stops being delivered. Depending on the path, you may see it as a bounce or as silent non-delivery. Either way, treat a disabled alias like any unreachable address and stop sending to it.
Does the relay break open and click tracking?
The relay itself forwards your mail intact, so links and pixels survive. The bigger factor is Mail Privacy Protection on Apple Mail, which can inflate open counts by pre-fetching images. Lean on clicks and downstream conversions rather than opens for these recipients.
For the authentication and reputation work that keeps relayed mail landing, see Bird's email deliverability product.