Email notifications are part of Azure DevOps' built-in functionality and are covered under your existing plan. Whether you're using Microsoft-hosted agents or self-hosted ones, notifications like pipeline status updates, work item changes, and code reviews are free to send. Sending email notifications for build success, failure, or other alerts does not incur extra charges.
There is no Microsoft official documentation stating this. But However, excessive notifications can lead to email throttling or spam filtering by your organization's mail server or client/
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