Introduction to Email Deliverability
Email deliverability refers to your ability to successfully deliver emails to subscribers' inboxes rather than their spam folders or being blocked entirely. It's influenced by a complex interplay of technical factors, content quality, sender reputation, and recipient engagement.
With average inbox placement rates hovering around 80% across industries, approximately one in five legitimate marketing emails never reaches its intended destination. For Shopify merchants, this translates to missed sales opportunities and wasted marketing efforts.
Email service providers (ESPs) like Gmail, Yahoo, and Outlook use sophisticated algorithms to protect their users from unwanted or potentially harmful messages. These algorithms evaluate hundreds of signals to determine whether your email deserves inbox placement or should be filtered out as spam.
The quality of your email list is far more important than its size. A smaller list of engaged subscribers will drive better results than a massive list of uninterested contacts.
Technical Factors That Send Emails to Spam
Technical issues form the foundation of email deliverability. Without proper authentication and infrastructure, even the best-written emails may never reach your subscribers. Here are the key technical factors that could be sending your emails to spam:
Missing Authentication Protocols
Email authentication protocols like SPF, DKIM, and DMARC verify your emails are legitimate and not forged by spammers. Without these protocols in place, ISPs may view your messages with suspicion.
Poor Sender Reputation
Your sender reputation is like a credit score for email senders. ISPs track your sending history and assign a reputation score that influences whether your emails reach the inbox.
Problematic IP Address
If you're sending emails from an IP address that has been used for spam in the past or is shared with other senders who have poor practices, your messages may be filtered regardless of your own sending behavior.
Inadequate Infrastructure
Technical issues like misconfigured mail servers, improper bounce handling, or unreliable hosting can negatively impact deliverability. These infrastructure problems signal to ISPs that you're not a professional sender.
Implementing proper technical foundations is the first step toward improved deliverability. Without these elements in place, even perfect content and engagement strategies may not be enough to reach the inbox.
Missing Unsubscribe Option
Failing to include a clear, functioning unsubscribe mechanism in your emails violates CAN-SPAM, GDPR, and other regulations. It also increases the likelihood that recipients will mark your message as spam when they want to stop receiving it.
Incorrect DNS Records
Proper Domain Name System (DNS) configuration is essential for email deliverability. Incorrect or missing records can prevent authentication protocols from working correctly and raise red flags with spam filters.
Need help optimizing your email deliverability?
Our email marketing experts can audit your current setup and implement technical improvements to ensure your messages reach the inbox.
Engagement and List Management Issues
Modern spam filters heavily consider how recipients interact with your emails. Poor engagement metrics and list management practices can significantly impact deliverability:
- 1
Low Engagement Rates
If your subscribers rarely open, click, or otherwise engage with your messages, ISPs may start routing them to spam folders. Focus on creating genuinely valuable content that encourages interaction and segment your audience to deliver more relevant messages.
- 2
Outdated Email Lists
Continuing to send to old, unengaged email addresses damages your sender reputation and increases the likelihood of hitting spam traps. Regularly clean your email list by removing long-term inactive subscribers and implement a sunset policy.
- 3
Purchased Email Lists
Buying email lists or scraping addresses from websites virtually guarantees deliverability problems. These contacts haven't opted in to receive your messages and are likely to mark them as spam. Always build your list organically through legitimate opt-in methods.
- 4
High Bounce Rates
Excessive bounces signal to ISPs that you're not maintaining your list properly. Immediately remove hard bounces from your list and monitor soft bounces, removing addresses that consistently bounce. Keep bounce rates below 2% for optimal deliverability.
- 5
Spam Complaints
When recipients mark your emails as spam, ISPs record these complaints. Even a relatively small complaint rate (above 0.1%) can severely damage your sender reputation. Make your unsubscribe process more visible than the spam button.
- 6
Inconsistent Sending Patterns
Erratic sending behavior, such as long periods of inactivity followed by large blasts, appears suspicious to ISPs. Establish a consistent sending schedule that your subscribers can anticipate and gradually increase volume rather than suddenly.
Pro Tip: Re-engagement Campaigns
Before removing inactive subscribers, try a targeted re-engagement campaign. Send a series of high-value emails specifically designed to win back dormant subscribers. Include compelling subject lines like "We miss you" or "Is this goodbye?" along with special offers or valuable content. Those who don't engage after this campaign can be safely removed from your list.
Download Our Free Email Deliverability Checklist
Get our step-by-step checklist to diagnose and fix email deliverability issues. Includes technical setup guide, content best practices, and engagement strategies.
How to Improve Email Deliverability
Now that we've covered the common issues that send emails to spam, let's look at a comprehensive approach to improving your deliverability:
Implement proper authentication
Set up SPF, DKIM, and DMARC records for your domain to verify your emails are legitimate and not forged.
Monitor and improve sender reputation
Use tools like Google Postmaster Tools or Sender Score to track and enhance your reputation over time.
Maintain clean, permission-based email lists
Regularly remove inactive subscribers and never purchase email lists or add contacts without permission.
Create engaging, valuable content
Focus on providing genuine value that encourages recipients to open, click, and interact with your emails.
Avoid spam trigger words and suspicious formatting
Steer clear of excessive promotional language, all caps, and too many exclamation points.
Maintain a good text-to-image ratio
Aim for at least 60% text to 40% images and ensure your message makes sense even if images are blocked.
Use clear, honest subject lines
Create subject lines that accurately reflect your email content and avoid misleading clickbait.
Include obvious unsubscribe options
Make it easy for recipients to opt out rather than marking your emails as spam.
Improving email deliverability is an ongoing process that requires consistent attention and refinement. Start by addressing the technical foundations, then focus on content quality and engagement strategies. Regularly monitor your performance metrics and make adjustments as needed.
Measuring Deliverability Success
How do you know if your deliverability is actually improving? Monitor these key metrics:
| Metric | Description | Target |
|---|---|---|
| Inbox Placement Rate | Percentage of emails that reach the inbox (not spam folder) | 90%+ |
| Open Rate | Percentage of delivered emails that are opened by recipients | 15-25% (industry dependent) |
| Bounce Rate | Percentage of emails that couldn't be delivered | Below 2% |
| Spam Complaint Rate | Percentage of recipients who mark your email as spam | Below 0.1% |
| Click-Through Rate | Percentage of recipients who click on links in your email | 2-5% (industry dependent) |
| Unsubscribe Rate | Percentage of recipients who opt out of future emails | Below 0.5% |
Consider using specialized deliverability monitoring tools like 250ok, Return Path, or GlockApps to get more detailed insights into your email performance across different ISPs and regions.
Common Deliverability Myths
There are several persistent myths about email deliverability that can lead marketers astray. Let's debunk some of the most common misconceptions:
Myth: Certain Words Automatically Trigger Spam
While spam trigger words exist, modern filters use sophisticated algorithms that consider context and overall email quality, not just individual words. A legitimate email with "free" won't automatically go to spam if other signals are positive.
Myth: Sending to Inactive Subscribers Is Harmless
Many marketers believe that sending to non-responsive subscribers has no downside. In reality, continued sending to inactive addresses significantly damages your sender reputation and increases the risk of hitting spam traps.
Myth: Authentication Is Optional
Some believe that SPF, DKIM, and DMARC are optional nice-to-haves. In reality, these authentication protocols are increasingly mandatory for inbox delivery. Major email providers like Gmail and Yahoo now require proper authentication, and emails without it are much more likely to be filtered or rejected.
Myth: One-Time Spam Issues Don't Matter
Some marketers believe that occasional deliverability problems won't have lasting effects. However, reputation systems have long memories, and recovering from even a single major spam incident can take months of consistent good sending practices.
The most damaging myth is that deliverability is out of your control. In reality, most deliverability issues can be prevented or resolved through proper technical setup, content quality, and list management practices.
Advanced Authentication Techniques
While basic authentication protocols (SPF, DKIM, DMARC) are essential, advanced senders can implement additional techniques to further improve deliverability and security:
BIMI (Brand Indicators for Message Identification)
BIMI allows you to display your brand logo next to your emails in supporting inboxes, increasing recognition and trust. It requires DMARC enforcement and a properly formatted SVG logo file.
MTA-STS (SMTP MTA Strict Transport Security)
MTA-STS helps secure email in transit by enforcing TLS encryption between mail servers, preventing man-in-the-middle attacks and ensuring email privacy during transmission.
ARC (Authenticated Received Chain)
ARC preserves authentication results when emails are forwarded, helping to maintain deliverability for messages that pass through multiple servers before reaching their final destination.
Implementing these advanced techniques can give you an edge in deliverability, especially for high-volume senders or those in industries with strict security requirements. Consider working with an email deliverability specialist to properly configure these protocols.
Need help optimizing your email deliverability?
Our team of experts can audit your current setup and implement technical improvements to ensure your messages reach the inbox.
Email Deliverability Checklist
Use this comprehensive checklist to systematically improve your email deliverability:
This checklist provides a quick reference guide to the most effective deliverability strategies for your Shopify store. Use it as a roadmap when planning your next email campaign or troubleshooting deliverability issues.
Conclusion: Building a Sustainable Email Strategy
Email deliverability isn't a mysterious force beyond your control—it's a set of technical and strategic factors that you can systematically address. By implementing the solutions outlined in this guide, you can significantly improve your inbox placement rates and ensure your marketing messages reach your customers.
Remember that deliverability is an ongoing process, not a one-time fix. Regularly monitor your performance, stay updated on best practices, and continuously refine your approach based on results. With persistence and attention to detail, you can transform your email marketing from a spam folder casualty to a reliable revenue driver for your Shopify store.
Start by implementing one or two of the strategies outlined in this guide, measure their performance, and refine your approach based on the results. With consistent testing and optimization, you'll develop an email strategy that effectively balances deliverability with engagement and conversion goals.
Key Takeaways
- Technical authentication forms the foundation of good deliverability
- List quality matters more than size—focus on engaged subscribers
- Content should be valuable and relevant, avoiding spam trigger patterns
- Regular list maintenance is essential for long-term deliverability
- Monitor key metrics to catch and address issues early
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