What is a transactional email?

A transactional email is an automated, non-promotional message sent from an application to a single recipient in response to a specific user action or event. Common examples include password resets, order confirmations, welcome emails, and account security alerts. Unlike bulk marketing email, their primary purpose is to convey critical information or confirm a process the user initiated.

The key distinction of transactional email lies in its one-to-one, event-driven nature. Because users expect and often depend on these messages, they have significantly higher open and engagement rates. This functional role also affords them different legal treatment; for example, under the CAN-SPAM Act, transactional messages are not required to have an unsubscribe link, as they are considered part of the core service.

Transactional emails are triggered programmatically by an application’s backend logic, typically via an API call or an SMTP relay. This event-driven approach enables the real-time delivery of context-specific information. Unlike bulk marketing, this email stream is a core part of the user experience. Therefore, maintaining a high-deliverability infrastructure is non-negotiable, as failures or delays—such as a password reset not arriving—can directly break functionality and harm the application’s perceived reliability.