---
title: Relay Domains
description: What email relay and forwarding services are, what relay_domain tells you, and how these addresses differ from disposable ones.
---

A relay service gives someone a stand-in address that forwards to their real mailbox. The sender never learns the real address, and the owner can switch off a stand-in at any time without affecting the mailbox behind it. Apple's Hide My Email, DuckDuckGo Email Protection, Firefox Relay, and SimpleLogin all work this way.

`relay_domain` is `true` when mail for the checked domain is handled by one of these services. That covers the service's own domains, and also a domain of your own whose mail is routed through a forwarding service, since the effect is the same either way: the address you were given is not the mailbox the mail ends up in.

The field is returned by the [domain](/docs/api/domain-endpoint) and [email](/docs/api/email-endpoint) endpoints, and is available in Gates as `domain.relay_domain`.

## Examples

| Domain | `relay_domain` | Why |
|--------|----------------|-----|
| `privaterelay.appleid.com` | `true`  | Apple's Hide My Email |
| `duck.com`                 | `true`  | DuckDuckGo Email Protection |
| `mozmail.com`              | `true`  | Firefox Relay |
| `gmail.com`                | `false` | A public mailbox provider, not a forwarding service |

## Your own domain can be flagged

`relay_domain` describes how a domain's mail is currently handled, not who registered it, so an ordinary company or personal domain is flagged while its mail is routed through a forwarding service. This catches people out most often when a registrar or DNS provider turns email forwarding on by default and the owner never set it up deliberately.

The flag follows the current setup. A domain that stops forwarding, by moving to a hosted mailbox or a self-hosted mail server, is reclassified. If you believe a domain is flagged incorrectly, [submit it for review](/submit-domain).

## What a relay address hides

Mail sent to a relay address reaches a real person who reads it, so the address is deliverable in a way that an address on a domain with no MX records is not. What the relay conceals is which mailbox is behind the address, and whether two addresses belong to the same person.

## Relationship to disposable domains

A disposable address expires on its own and its mail is discarded. A relay address stays live and forwards to a mailbox the owner still reads, until they choose to disable it. `disposable` and `relay_domain` are separate fields, and each answers only its own question. See [Disposable Domains](/docs/concepts/disposable).

A forwarding service that handles a domain's mail also appears in `mx_providers` with a `type` of `forwarding`. See [MX Providers](/docs/concepts/mx-providers).

For background on how forwarding works, see [What is Email Forwarding](/guides/what-is-email-forwarding).