High Volume Email (HVE) for Microsoft 365 allows customers to send large volumes of email, primarily to internal recipients without any recipient rate limits at GA (the public preview has a limit of 100,000 recipients per day per tenant).
HVE is a companion feature to Azure Communication Services (ACS) for email, which offers high-volume transactional, bulk, and marketing emails to external recipients. The public preview of HVE was released on April 1, 2024.
Today, we’re excited to announce some new enhancements to the HVE public preview.
Added Support for OAuth
Support for OAuth is now available in the public preview. The benefits of using OAuth include enhanced security and seamless integration with Microsoft 365. You can use application or delegated permission. Instructions for enabling OAuth for HVE are at OAuth authentication for high volume emails for Microsoft 365.
Improved Account Setup
In addition to adding support for OAuth, we have also enhanced the experience in Exchange admin center for account setup. You can now select your managed domain via a drop-down menu as shown below.
Final Naming for PowerShell Cmdlet Parameters
We have renamed the LOBAppAccount parameter for the New-MailUser cmdlet to HVEAccount. An example of the finalized naming is shown below:
New-MailUser -HVEAccount -Name "TestAccount@contoso.onmicrosoft.com" -PrimarySmtpAddress "TestAccount@contoso.com”
The previous LOBAppAccount parameter will be available for a short while, but we will begin phasing it out in the coming weeks.
Support for Federated Domains
Federated domains are now compatible with HVE accounts. To implement HVE for a federated domain, use the following command where contoso.com represents a federated domain. Any managed domain can now be included in the Name field.
New-MailUser -HVEAccount -Name "TestAccount@contoso.onmicrosoft.com" -PrimarySmtpAddress "TestAccount@contoso.com”
General Availability
We are targeting general availability starting September 2025 and expected to be completed by early October 2025. Our focus for the public preview is to ensure stability and reliability and introduce additional features like billing and reporting.
We’d love to get your feedback on HVE! Feel free to leave your comments and feedback below.
Microsoft 365 Messaging Team