Plus Addressing in Exchange Online

What is plus addressing?

Plus addressing, also known as sub-addressing, allows you to create variations of a normal email address that will still be delivered to your institutional email account.

An email address uses the basic syntax: @. For example, bsomeone@astate.edu.

Plus addressing uses the syntax: +@. For example, bsomeone+newsletter@astate.edu.

The original email address must be valid. The +tag value that you add is arbitrary, but it cannot contain spaces.

Plus addressing can be used in any email client that sends emails and you can receive emails addressed to you using plus addresses as you would normal emails.

Using plus addressing

To use this feature, append a + sign and desired descriptor after your account name and before the @ symbol (e.g., bsomeone+prtcommittee@astate.edu). 

You cannot send from a plus address.

Some web forms don't support plus signs in email addresses.

As plus addresses are not aliases that are configured on the mailbox, they don't resolve to a user's name in Outlook clients. This limitation results in plus addresses being easily identifiable in the To or CC fields of messages. However, there might be scenarios where you can't use a plus address for a Microsoft service that needs to be associated with your mailbox.

To automatically identify and filter messages that are sent to plus addresses, use Inbox rules to act on those messages. Using the condition Recipient address includes, you can specify an action for messages sent to a particular plus address. For example, you can move messages sent to a plus address to a folder.

Plus addressing may be used on user, distribution group and M365 group email addresses.

Why Use Plus Email Addressing? 

The full address, including the extra information, can act as a label and can be useful for managing email and site registrations. Here are two examples:

1. Use plus addressing when you sign up for different newsletters or community lists to easily filter or create rules for them, which can help you organize, search, and file the messages you receive from those senders.

2. Plus addressing is useful for creating disposable addresses that can prevent spam from coming to your mailbox. If you need to enter your email address in a form, you can enter a variant address in that form. After you get the required email, you can set up a block to never receive an email at that address again.