What ghost aliases are and how they work

A Ghost Alias is a temporary email address that delivers your mail to your normal inbox without exposing your real email address. It works like any other email address while it is active, but it has an expiry date, and once that date passes, it is automatically removed. This blog post will explain what Ghost Aliases are, how to create one, and what happens over its lifetime.

What a ghost alias looks like

Ghost aliases are created on the astermail.org domain, and each address is made of two common words and a short random string. Here is an example:

sage.frost7k2x9q@astermail.org

The random portion is generated on your device, and there is a way to keep addresses from being guessed or linked to another one. The words simply make the address easier to read and say out loud.

What they are for

A ghost alias is useful any time you need to provide an email address but do not want to give out your real one. Some common examples include:

• Signing up for a free trial, a download, or a one-time discount.
• Registering on a marketplace or forum you may not use again.
• Filling in a form when you are unsure how the address will be handled.

Because each alias can be retired or left to expire, mail tied to it stops being delivered once you are done with it. Your main address is never shared in the first place.

How your privacy is protected

The readable name of the ghost alias is encrypted on your device before it is sent to Aster. The server only stores the encrypted name and a one-way value used to route incoming mail. This means Aster can deliver messages right to your inbox without being able to read the alias itself, and your real address is never revealed to people you give the alias to.

Creating a ghost alias

Ghost aliases are created from the Compose screen, rather than from a separate settings page. Whenever you start a new message, you can turn on Ghost Mode and a new address is generated for that message. You can choose how long the alias should remain active: 7 days, 30 days, or 90 days.

From that point on, an alias will behave like a normal address, and mail sent to it will arrive in your inbox. Whenever you reply, the recipient will see the ghost alias as the sender and never your real one. A list of all your ghost aliases (active and expired) is available in your settings under the Ghost Aliases tab.

What happens when an alias expires

Ghost aliases are designed to clean themselves up, and they move through a couple of stages:

• While active, the alias receives mail and forwards it to your inbox.
• When the expiry date passes, the alias is disabled and stops accepting new mail. Mail you already received stays in your inbox; expiry does not delete it.
• The alias then enters a 30-day grace period before it is permanently removed. During this time it does not receive new mail; it has simply not been deleted yet.
• After the grace period, the alias is deleted automatically.

You can extend an active alias if you need more time, up to a maximum of 90 days from when it was created. You can also expire an alias yourself, but only once it is at least 30 days old. New aliases should remain active for the first month, which prevents the feature from being used to cycle through addresses rapidly.

Replies within a conversation

If a ghost alias is used during an ongoing exchange, Aster keeps that alias associated with the conversation. Whenever you reply later, the same ghost address is used automatically, so the other person continues to see a single consistent sender.

How many you can create

On the free plan, you are able to create up to five ghost aliases each month. The count resets at the start of every new month. Paid plans do not have this monthly limit, and there is no limit on how many aliases can be active at the same time. The monthly figure only counts how many new ones you create.