It is important to understand the difference between a transactional e-mail and a marketing e-mail.
A marketing e-mail is an e-mail which target contacts (simultaneously) all together to inform them via global communications about your products, campaigns, promotions.
They can take the shape of a newsletter for example.
Unlike marketing e-mails, transactional e-mails are sent to a specific and unique recipient to confirm an action, a transaction or notify an event, such as:
- A registration confirmation
- A password reset confirmation
- A personalized notification
- Sending an invoice
From a practical point of view, your marketing campaigns are sent or scheduled manually by setting a date and time, while transactional e-mails are automatically triggered and sent instantly based on an action or event.
In general, a transactional e-mail will use the SMTP Relay, although this is not always the case.
The SMTP Relay is not subject to the different blacklists, unlike marketing e-mails, as those two platforms are technically separated.