Send High Volume Email in Microsoft 365

Early February 2024, posts appeared online with screenshots of the Exchange Online Admin Center showing what seemed to be a new page named High Volume Email. The description is:

High Volume Email is a service to send mass mailing communication using SMTP endpoint. Note: you can add up to 20 High Volume Email accounts.

This description is somewhat elusive, but it clearly suggests that Microsoft is soon to release a new feature to rival that of 3rd-party mailing services that marketing teams have grown to love. However, it fails to provide any context, details or a link to the relevant documentation on Microsoft Learn, which they are known for providing.

Update: 15/02/2024

High Volume Email has now been added to the M365 Roadmap! Item 382633

Exchange: High Volume Email for Microsoft 365

High Volume Email is a new service for line of business applications and other high-volume SMTP scenarios that enables you to send internal messages beyond the current limits of Exchange Online.

  • Feature ID: 382633
  • Added to roadmap: 2/15/2024
  • Last modified: 2/15/2024
  • Product(s): Exchange
  • Cloud instance(s): Worldwide (Standard Multi-Tenant)
  • Release phase(s): Preview, General Availability

So what do we know about High Volume Email?

Well, posts first appeared online on Monday 5th of February on platforms such as Reddit and the Microsoft Technical Community forums. Users online also mentioned recent updates to the Exchange Online Service Descriptions doc on Microsoft Learn, but nothing to this degree and the GitHub page is currently locked down to view the edits.

Currently, little is known about the service limits, restrictions or use cases for high-volume emails in Exchange Online. Upon creating an account, you are just asked for the Display name, Primary email address and password.

New High Volume Email account
New High Volume Email account

User Dan Jansson posted an article on Medium showing his findings.

It turns out, as expected that this service utilised SMTP authentication, something previously legacy and disabled tenant-wide by default through the use of Security Defaults. To get this working, Dan had to manually enable SMTP authentication on the newly created High Volume Email account; after some waiting, he could successfully connect to the mailbox and send an email.

Questions about the service were taken to Microsoft’s official technical community forum, but just a single response was provided by Microsoft Employee Scott Schnoll…

High Volume Email response
High Volume Email response

LinkedIn user Roel van der Wegen managed to make a POST request to the admin.exchange.microsoft.com/beta/MailUserIC endpoint while the feature was live to create a new High Volume Email account. While the recipient type was not abnormal for an Exchange Online user, a BulkMailEnabled property was present with the value of True.

Use cases for High Volume Email

This feature could quickly become a game-changer for organisations that need to send bulk mail messages. However, in my opinion, it is not a replacement for reputable 3rd-party bulk mailing solutions.

Microsoft has a reputation of ‘Do it yourself’; you get the platform, but it’s up to you to make it work. This includes security, integrations and all the rest. Any 3rd party solution will include all the additional tools to help generate and distribute emails in bulk, whereas Microsoft just gives you a working endpoint. The absolute best option for these 3rd party marketing vendors is to enable customers to integrate their solutions with Microsoft High Volume Email service, potentially at a lower or adjusted subscription model.

That being said, some use cases for High Volume Email might include:

  • Newsletters
  • Web form submissions
  • Alerts or notifications
  • CRM integrations 
  • Migration scenarios 
  • High volume scanning

Wrapping up

Wrapping up… this could be a great addition to the Exchange Online service, not that they currently have much competition in the corporate world. But little is known about the limitation, and dare I say it: cost! As with anything, adding a potentially significant load to a computer service will increase costs and currently in the unknown amounts. Let’s see if Microsoft provide an official response before the feature release, TBD.

Daniel Bradley

My name is Daniel Bradley and I work with Microsoft 365 and Azure as an Engineer and Consultant. I enjoy writing technical content for you and engaging with the community. All opinions are my own.

This Post Has 2 Comments

  1. Martijn Goudkamp

    Super news! Was here to learn more about Powershell and this article was a good surprise! Bedankt!

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