SMTP (Simple Mail Transfer Protocol) warm-up is a process used to gradually increase the volume of emails sent through a specific SMTP server or IP address to establish a positive sending reputation.
This practice is essential to improve deliverability
and ensure that emails reach recipients' inboxes rather than being marked as spam. SMTP warm-up is typically used when using a new SMTP server or IP address or when significantly increasing email sending volumes.
Every email service provider has its own set of algorithms, or filters, that are designed to detect spam emails, or those that are potentially harmful to their users.
You need to establish a positive sender reputation
with these filters to ensure your emails are not flagged and delivered to subscribers’ inboxes.
This is why Unfiltered is set up with SMTP.