Exchange Online HVE (High Volume Email) – Bulk Communications for Internal Recipients

This article delves into Microsoft Exchange Online HVE (High Volume Email) key capabilities, use cases, setup process, and best practices for optimizing high-volume email workflows.

What is High Volume Email (HVE) in Exchange Online?

Exchange Online High Volume Email (HVE), in preview since April 2024, is designed to support organizations that need to send large volumes of bulk emails reliably, without being hindered by standard throttling limits or spam filtering mechanisms. Exchange Online HVE is a cloud service based on Exchange Online.

During the preview period, Microsoft offers up to 100 HVE accounts per tenant/customer for free. The service is expected to become pay-as-you-go when it becomes generally available in September 2025.

HVE is for internal mass communication. The preview previously allowed up to 2,000 external recipients per day, but Microsoft announced earlier this year that Exchange Online HVE will be for internal recipients only when it reaches general availability later in 2025. 

The ability to send to external recipients has now been removed from Exchange Online HVE. If you are looking to send external emails in bulk, Azure Email Communication Services (ECS) is Microsoft’s pay-as-you-go solution.

Important – according to Microsoft, any efforts to bypass this limit will be noticed and emails not delivered.

Currently, HVE supports SMTP basic authentication, but you will need to transition to modern authentication by September 2028.  OAuth authentication support was added to the preview in October 2024.

How is HVE different from standard Exchange Online mailboxes?

Let’s look at the basic differences between High Volume Email (HVE) and standard user mailboxes, and the current limits in Exchange Online.

Feature	Standard Exchange Online	High Volume Email (HVE)
Sending Limits	Strict throttling (~10k/day)	Scalable, high-throughput sending
Use Case	Day-to-day business email	Automated/bulk messaging
Spam Filtering	Default protections apply	Optimized for bulk deliverability

How to set up an Exchange Online HVE account

The setup of a new HVE account is straightforward. The only nuance is that it is a special account (a unique type of Exchange mailbox), so you will use another portion of the Exchange admin center website and an exclusive switch in PowerShell.

Next, I’ll give you a high-level overview of how to setup a new High Volume Email (HVE) account.

Create an Exchange Online HVE account

• Starting in the Exchange (Online) Admin Center website…
• Browse to Mail flow -> High Volume Email (Preview). Click ‘Add an HVE account‘.

• Fill in the Display name field, enter a Primary email address and your email domain name from the dropdown.
• Then, enter an optional alias, and the initial password for the account.
• Click Next.

• A review screen will come up showing the details. If all is good, click Create.

Using PowerShell for HVE creation and management

Before we create another HVE mailbox, let’s use PowerShell to display the one we just created with the GUI.

• Connect to Exchange Online and type in this command:

Get-MailUser -HVEAccount

Let’s create our second HVE account. Use the command below to create another account with PowerShell. You’ll be prompted for the new password after executing the command.

New-MailUser -HVEAccount -Name "High Volume Email - Number 2" -PrimarySmtpAddress "[email protected]"

You can delete/remove one of these accounts by using this command as an example.

Remove-MailUser -Identity "HVE account"

Usage reporting

Microsoft provides an easy mechanism to generate a detailed report for the HVE feature. Although I don’t have a tenant with real-world usage, I will still show you how to generate a report. Again, we’re back in the Exchange Admin Center website.

• Browse to Reports -> Mail flow. Under Mail flow reports, select High Volume Email (Preview).

Again, there isn’t any data here, yet.

After you are presented with the data, you can select a specific “sender address”, “usage data”, a “selected period” in time, and even only “internal messages.” Choose which parameter(s) work best for your needs.

You can also use “request report” to get a detailed report showing the messages sent using HVE.

Key benefits

The benefits of this service revolve around the increased ability to send large-scale transactional or bulk emails reliably. Let’s go through the primary advantages.

1. Higher sending limits and improved throughput

• Bypasses standard throttling (e.g., 10,000 recipients/day per mailbox). There’s no upper limit with Exchange Online HVE.
• Faster processing with dedicated routing for bulk messages, reducing delays in time-sensitive communications (e.g., OTPs, alerts).

2. Security and compliance

• Built-in Microsoft 365 security (ATP, anti-phishing, malware scanning) applies to HVE mailboxes.
• Supports regulatory requirements (GDPR, HIPAA) with encryption and audit capabilities.
• Microsoft’s abuse monitoring helps prevent misuse while allowing legitimate bulk sending.

Limitations

There are limitations with the service. Let’s go through the major ones here.

• Throughput varies based on Microsoft’s infrastructure load (unlike dedicated third-party ESPs with SLA-backed speeds).
• No real-time send guarantees – Large batches may experience minor delays during peak times.
• SMTP authentication & API knowledge needed for custom integrations.

Frequently asked questions

What is Microsoft High Volume Email?

Microsoft High Volume Email (HVE) is a feature designed to handle large-scale email sending within Exchange Online. It is typically used for automated alerts, notifications, or system-generated messages that need to reach many internal recipients efficiently while staying compliant with Microsoft 365 email policies.

Is Microsoft High Volume Email free?

Microsoft High Volume Email is included with Exchange Online and Microsoft 365 plans, so there is no separate cost for the feature itself while in preview. Once Exchange Online HVE reaches general availability in 2025, it’s expected that Microsoft will charge for its use on a pay-as-you-go basis.

What does Exchange Online do?

Exchange Online is Microsoft’s cloud-based email and calendaring service that provides secure email hosting, integrated spam and malware protection, and easy access from any device. It eliminates the need to maintain on-premises mail servers and integrates with Microsoft 365 apps for seamless collaboration and productivity.