Email deliverability is often confused with email delivery, but they represent two very different concepts that are crucial to understand for anyone sending emails at scale.
Email Delivery vs. Email Deliverability
Email delivery simply refers to whether an email was accepted by the receiving server. If your email doesn't bounce back with an error message, it was technically "delivered." However, this doesn't tell you anything about where that email ended up.
Email deliverability, on the other hand, refers to the ability to deliver emails to recipients' inboxes rather than their spam or junk folders. This is what really matters for email marketers and businesses.
Why Deliverability Matters
You could have a 99% delivery rate (meaning very few bounces), but if 50% of those "delivered" emails are landing in spam folders, your actual reach is severely compromised. Most users rarely check their spam folders, meaning those emails might as well have bounced.
Good deliverability ensures that:
- Your messages reach your intended audience
- Your email marketing ROI is maximized
- Your sender reputation remains strong
- You avoid being flagged as a spammer
Factors Affecting Deliverability
Email deliverability is influenced by numerous factors:
Technical Factors
- Authentication protocols (SPF, DKIM, DMARC)
- IP reputation of your sending servers
- Domain reputation associated with your sending domain
- Infrastructure setup and configuration
Content Factors
- Email content including text, images, and code
- Subject lines and how they're crafted
- Spam trigger words and phrases
- Text-to-image ratio in your emails
Engagement Factors
- Open rates from your subscribers
- Click-through rates on your links
- Reply rates to your messages
- Spam complaint rates from recipients
List Hygiene Factors
- Bounce rates from invalid addresses
- List quality and acquisition methods
- Unsubscribe handling and compliance
- Sending frequency and volume patterns
Measuring Deliverability
Accurately measuring deliverability can be challenging, but several approaches can help:
- Seed testing: Sending to a network of test accounts across different ISPs
- Deliverability tools like SpamBarometer that analyze technical and content factors
- Inbox placement monitoring to track where your emails land
- Engagement metrics as indirect indicators of deliverability issues
Conclusion
Understanding email deliverability is the first step toward improving it. By recognizing that delivery and deliverability are distinct concepts, you can begin to focus on the factors that truly impact whether your messages reach the inbox.
In the following guides, we'll explore specific strategies and techniques to improve each aspect of email deliverability, from technical setup to content optimization.