Frequently Asked Questions

What is a ⁨Relay⁩ alias?

Email aliases are masked email addresses that forward messages to your true email address. These aliases allow you to share an address with third parties which will mask your true email address and forward messages to it.

I’m not getting messages from my aliases

There are a few reasons you might not be receiving emails forwarded through your aliases. These reasons include:

  • Messages are going into spam
  • Your email provider is blocking your alias
  • The email forwarded has an attachment larger than ⁨⁨150⁩ ⁨KB⁩⁩
  • The site doesn’t accept aliases
  • The alias might have forwarding turned off
  • ⁨Relay⁩ might be taking longer than usual to forward your messages

If you’re struggling with any of these issues, please visit our support site.

When should I use ⁨Relay⁩ aliases?

You can use ⁨Relay⁩ aliases most places you’d use your regular email address. We recommend using them when signing up for marketing/informational emails where you may want to control whether or not you receive emails in the future.

We don’t recommend using aliases when you need your identity verified or for very important emails or those where you must receive attachments. For example, you’d want to share your real email address with your bank, your doctor, and your lawyer, as well as when receiving concert or flight boarding passes.

Why won’t a site accept my ⁨Relay⁩ alias?

Some sites may not accept an email address that includes a subdomain ( and others have stopped accepting all addresses except those from Gmail, Hotmail, or Yahoo accounts. If you are not able to use a ⁨Relay⁩ alias, please let us know.

What about spam?

While ⁨Relay⁩ does not filter for spam, our email partner Amazon SES does block spam and malware. If ⁨Relay⁩ forwards messages you don’t want, you can update your ⁨Relay⁩ settings to block messages from the alias forwarding them.

If you see a broader problem of unwanted email from all of your aliases, please report this to us so we can consider adjusting the SES spam thresholds for this service. If you report these as spam, your email provider will see ⁨Relay⁩ as the source of spam, not the original sender.

Where is ⁨Relay⁩ available?

Free ⁨Relay⁩ is available in most countries. ⁨Relay Premium⁩ is available in the United States, Germany, United Kingdom, Canada, Singapore, Malaysia, New Zealand, France, Belgium, Austria, Spain, Italy, Switzerland, Netherlands, and Ireland.

Can I reply to messages using my ⁨Relay⁩ alias?

⁨Relay Premium⁩ users can reply to a forwarded email within 3 months of receiving the email. If you add a CC or BCC when you reply back to an email, your original email address will be exposed to the recipient and those copied on the email. If you do not want your original email address exposed, do not add CCs or BCCs when replying.

What characters can I use to create a subdomain?

You can only use lower-case English letters, numbers, and hyphens to create a subdomain.

Can I use ⁨Relay⁩ on other browsers or my mobile device?

Yes, you can generate ⁨Relay⁩ aliases on other browsers or mobile devices simply by logging in to your ⁨Relay⁩ dashboard.

What happens if Mozilla shuts down the ⁨Firefox Relay⁩ service?

We will give you advance notice that you need to change the email address of any accounts that are using ⁨Relay⁩ aliases.

Why did my aliases start to use the domain “”

We made the switch from “” to “” in order to make it possible to get a custom email domain, such as Custom email domains, available to ⁨Relay Premium⁩ subscribers, also make your email aliases much easier to remember than random aliases.

Will ⁨Firefox Relay⁩ forward emails with attachments?

We now support attachment forwarding. However, there is a ⁨⁨150⁩ ⁨KB⁩⁩ limit for email forwarding using ⁨Relay⁩. Any emails larger than ⁨⁨150⁩ ⁨KB⁩⁩ will not be forwarded.

What happens to my custom domain if I unsubscribe from ⁨Relay Premium⁩?

If you downgrade from ⁨Relay Premium⁩, you’ll still receive emails forwarded through your custom domain, but you’ll no longer be able to create new aliases using that domain. If you have more than five aliases in total, you will not be able to create any more. You’ll also lose the ability to reply to forwarded messages. You can resubscribe to ⁨Relay Premium⁩ and regain access to these features.

What data does ⁨Firefox Relay⁩ collect?

You can learn more about the data ⁨Firefox Relay⁩ collects by taking a look at our Privacy Notice. You’re also able to optionally share data about the labels and site you use for your email aliases so we can provide you that service and improve it for you.

Does ⁨Relay⁩ store my emails?

Under the rare circumstance in which the service is down, we may temporarily store your emails until we are able to send them. We will never store your emails for longer than three days.