Your username is the email address you use to log in to your Fastmail account.
You must use your username
For security purposes, you cannot change a username more than twice every seven days, or more than once in 24 hours. Your username cannot be changed during your trial period.
If you are on a multi-user account, you must have admin access to change your username or the username of any other user in your account.
To change a username:
- Go to the Settings → Users & Sharing screen.
- Click the user you want to rename.
- Find the Username heading and click Rename.
- Enter what you'd like your new username to be. Check your new address to make sure it's exactly what you want.
- Be sure to click Save.
When you change a username, the old username will be automatically added as an alias, so it will still be able to send and receive messages. If you don't want to send or receive messages at your old username, you can delete the alias on the Settings → Users & Sharing screen.
Username limitations
Hyphens
Due to an internal technical limitation, we cannot allow hyphens (-) in any usernames, or in aliases at Fastmail-owned domains.
Hyphens are allowed in aliases at your own custom domain only.
How dots and underscores are handled in usernames
Dots (.) and underscores (_) are treated the same in usernames. This means you can receive mail sent to either version of your username.
For example, if your username is hannah_martin@teachdev.io, you can receive mail sent to both hannah.martin@teachdev.io and hannah_martin@teachdev.io.
How dots and underscores are handled in aliases
Dots and underscores are treated as different characters in aliases. Using the above example, hannah.martin@teachdev.io and hannah_martin@teachdev.io would be treated as two separate email addresses.