The ability of an email message to reach the recipient’s inbox rather than being blocked, rejected, or filtered as spam.
Deliverability depends on sender reputation, authentication, list quality, and engagement.
Short and sweet:
The ability of an email message to reach the recipient’s inbox rather than being blocked, rejected, or filtered as spam.
Deliverability depends on sender reputation, authentication, list quality, and engagement.
See also: Email Marketing, Open Rate, Email Automation
Email deliverability measures whether messages actually reach a subscriber’s inbox rather than being filtered to spam or blocked outright, which is a separate question from whether an email was simply sent. It depends on technical factors like domain authentication and sender reputation as much as it does on list hygiene and how recipients engage with past sends. A campaign with strong open rates on paper can still be underperforming if deliverability issues are quietly keeping a portion of the list from ever seeing it.
Gmail’s spam filters will quietly route a Mailchimp campaign straight to the Promotions tab, or worse the spam folder, if the sender hasn’t set up proper SPF and DKIM authentication records, a clear email deliverability failure.
A retailer like Sephora invests heavily in list hygiene, regularly removing inactive subscribers so that its promotional blasts keep landing in real inboxes instead of tanking its sender score.
When a company switches email service providers, say from Constant Contact to Klaviyo, it often sees a temporary dip as the new sending domain has to rebuild trust with inbox providers like Outlook and Yahoo.
