Email Deliverability

What is Email Deliverability?

Email deliverability refers to the likelihood that your email will arrive in the recipient's inbox (as opposed to the spam folder, or not being delivered at all). It's determined by a combination of your sender reputation, email authentication, content quality, and list hygiene.

Deliverability is often confused with delivery rate. Delivery rate measures whether the email was accepted by the receiving server (not bounced). Deliverability measures whether it actually reached the inbox — a much higher bar, since an email can be "delivered" but still land in spam.

Factors That Affect Deliverability

• Sender reputation — ISPs score your sending IP and domain based on historical behaviour (complaints, bounces, engagement).
• Authentication — Properly configured SPF, DKIM, and DMARC prove you're a legitimate sender.
• List quality — Sending to invalid, inactive, or purchased addresses generates bounces and spam complaints.
• Content — Spam trigger words, excessive images, missing unsubscribe links, and poor HTML can trigger filters.
• Engagement — High open and click rates signal to ISPs that recipients want your email.
• Blacklists — Being listed on DNS-based blacklists (DNSBLs) will severely impact deliverability.

How to Improve Deliverability

1. Set up SPF, DKIM, and DMARC for your sending domain.
2. Validate email addresses before adding them to your list.
3. Regularly clean your list by removing bounced and inactive addresses.
4. Monitor your sender reputation and blacklist status.
5. Warm up new IPs/domains gradually.