Glossary
Email

Email Deliverability

The ability of emails to successfully reach recipients' inboxes rather than spam folders.

Email deliverability measures whether your emails reach the inbox, go to spam, or get rejected entirely. It's affected by sender reputation, authentication, content, and technical configuration.

Factors Affecting Deliverability:

Sender Reputation:

  • Domain age and history
  • Sending volume patterns
  • Complaint rates
  • Bounce rates
  • Engagement metrics

Authentication:

  • SPF records configured
  • DKIM signing enabled
  • DMARC policy set
  • All three aligned properly

Content Quality:

  • Spam trigger words avoided
  • HTML properly formatted
  • Good text-to-image ratio
  • Clear unsubscribe option

Technical Setup:

  • Valid MX records
  • Proper IP configuration
  • Consistent sending patterns
  • Clean email lists

Measuring Deliverability:

  • Inbox Placement Rate: % reaching inbox
  • Bounce Rate: % undeliverable (aim for <2%)
  • Spam Complaint Rate: % marking as spam (aim for <0.1%)
  • Open Rate: Indirect deliverability signal

Improving Deliverability:

  1. Set up SPF, DKIM, DMARC
  2. Warm up new domains/IPs
  3. Clean email lists regularly
  4. Monitor sender reputation
  5. Maintain consistent volume

Why It Matters

Poor deliverability means your emails don't get seen, wasting marketing efforts and missing important communications. For cold email, it's the difference between success and failure.

Practical Example

Your cold email campaign shows 15% open rate when it should be 40%. You check and find no DKIM record. After adding it, your next campaign hits 38% opens—the emails now reach inboxes instead of spam.

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