Plus Addressing in Outlook and O365

Plus addressing is adding a “filter” or a suffix or tag to your existing email address so that you can filter incoming email by making your own email dynamic.

Lets say you have as your primary email, you can use john+<suffix> or and use that to register to netflix. Emails sent to still delivers to your mailbox.

For an instance, you want to sign-up for a subscription. Do not just put your whole email address. Try adding “+subscription” where the name of the subscription that you are registering to.


Once a mail arrives in your mailbox, it should be something like this. Notice also that the “to:” field contains the suffix or keyword that you used.


What are the possible use cases and possibilities?

  • For one, it helps you track down which company, spammer, subscription that your email came from. Even if they “sell” your email, and the “from” changes, the sub / tag / will still be there.
  • Use mail filter, automatic spam? Categorize? Move to folder.
  • Have multiple email addresses.
  • Alternative to disposable emails. Long stretch but possible, right?

Geek section!

This is actually an implementation of 2004 RFC3696 or better known as “Application Techniques for Checking and Transformation of Names

Lookup section #3 for Email Addresses and #4.3 for Mail-To URL’s


So for the longest time, this has been available in other public emails like in Gmail, its called “task-specific email addresses”

Or something like this from 2008:


Exchange and Office 365

Office 365 did not support this. Well at least until Sept. I was waiting for this feature since it was announced or at least I saw on uservoice that it will be available Q4 of 2020. It may have seemed to arrive earlier or on time for Q4 . So revisiting this and applying to my own O365 E3 Tenant.

To implement on O365:

On my freshly updated PC (with internet connectivity):

1. Run PS in Admin

2. Set-ExecutionPolicy RemoteSigned

3. Install-Module -Name ExchangeOnlineManagement

4. Import-Module ExchangeOnlineManagement

5. Connect-ExchangeOnline –UserPrincipalName <user>@<o365domain>.com -ShowProgress $true

6. Set-OrganizationConfig -AllowPlusAddressInRecipients $true


Lets try it out on my Office 365 Email: Suppose I wanted to use my email to re-subscribe to coursera:

I use


It arrives to my office 365 mailbox as:


PS. Apologies for the redaction. Some re-bloggers and bots are mining my blog pictures and screenshots may end up on other sites that shows my naked email. But I do hope it came across.

PPS. I got a few spam mails and I this is why I revisited this in the first place. Hoping that I can at least help exchange mailbox filter out nasty emails. Again, apologies for the redaction.


How to disable clutter [Fixed]

Send Grid never failed me, I had never used the plain’ol SMTP way back when I started using Azure. But today, I have been pulling my hairs out because it seems my password reset is not sending any email.

I checked, double checked my IIdentityMessageService implementation and I know this works. I changed to my personal Office 365, refreshed it again and still no avail. But wait, what is this? Clutter. Clutter is a feature already as described here.


To turn this off, go to your Mail options by clicking the cog in the right hand corner and then click  options.

Navigate to Options > Mail > Automatic Processing > Clutter.


Uncheck “Separate items identified as clutter. Then click save.


There ya go, now back to the forgot password thingy.