ProtonMail offers the ability to receive mail to an unlimited number of aliases by using a “+” symbol after your username in your email address. For example, if your username is email@example.com, you can also receive emails to firstname.lastname@example.org, email@example.com, etc.
You can only use an alias to receive emails, not to send.
There is no need to ‘set up’ or ‘create’ an alias in your user settings. Rather, a new alias is created whenever someone sends you an email to that alias.
Aliases are useful for a variety of reasons. For example, you may want to post an alias instead of your main email address on your public website or social media accounts to help identify spam.
Aliases are especially helpful for organizing your inbox in combination with filters. You can create a custom label or folder for all emails sent to a particular alias. For example, you could ask invitees to your wedding to respond to the alias firstname.lastname@example.org. Then, in filters, you can automatically apply the label “Wedding” to all mail sent to that alias. Learn how to create filters here.
Aliases, addresses, and users
Aliases, addresses, and users are not the same thing in ProtonMail. While free users can have unlimited aliases, adding addresses and users are only possible for paid plans.
Addresses are unique email addresses that do not use the “+” symbol. All paid accounts can add additional email addresses using one of the ProtonMail domains (i.e. protonmail.com, protonmail.ch, or pm.me) or using a custom domain. Those with multiple ProtonMail accounts can merge their addresses into a single account in order to send and receive mail from the same mailbox. For example, if you have a Plus plan, you could have your main address as email@example.com and also receive mail to an additional address like firstname.lastname@example.org. Unlike aliases, you can change the display name and signature for each address.
Users are a feature of ProtonMail for business that allows account owners to create multiple, unique email addresses within an organization. Only Professional and Visionary accounts can add additional users. Once you have created an organization with a custom domain, you can add users to your organization. (Users cannot be added with ProtonMail domains.) For example, you could create email@example.com, firstname.lastname@example.org, email@example.com, etc. These users may be private (meaning the account owner does not have access to the user inbox) or non-private.