Email Deliverability

Email deliverability is the ability to deliver emails to subscribers’ inboxes. It is what some marketers use to gauge the likelihood of their email campaigns reaching their subscribers’ inboxes related to actual delivery–like ISPs, throttling, bounces, spam issues, and bulking.

Elements that hurt deliverability include sending without custom authentication, using single opt-in, sending from a free domain email address, making it difficult to unsubscribe, using URL shorteners, and lack of engagement.

In terms of delivery, email service providers (ESPs) show why a message was rejected (bounced), based on the details the receiving server sends back in the error message.

Campaign Monitor’s email software can accurately measure delivery rates to know how many emails are accepted and how many bounce. Examples of bounced emails include a temporary delivery error (soft bounce) because the server is unavailable, or a permanent error (hard bounce) because the email address is no longer valid.

Campaign Monitor has an overall delivery rate of 99%. Although we are unable to know what percentage of emails arrive in the inbox vs. the spam folder, we can make informed inferences by analyzing metrics.

Bounce rates (tracked by the ESP), open rates, unsubscribe rates, click-through rates, and spam complaints give the marketer insight as to how people react to and engage with their emails. Monitoring these metrics over time reveals trends in audience activity and engagement.

With deliverability, engagement is the most important factor, since it directly impacts sender reputation (both for the marketer and the ESP). A stellar sender reputation is key to great email deliverability.

Here are a few things to keep in mind (for more tips, check out our post on improving email deliverability):

• Maintain list hygiene
• Keep an eye on inactive subscribers
• Send using custom authentication
• Using double rather than single opt-in
• Make it really easy to unsubscribe
• Avoid using URL shorteners