What is Email Deliverability?
Quick Answer
Email deliverability is the ability of an email to successfully reach the recipient's inbox rather than being filtered into spam or rejected entirely. It measures how well your emails pass through spam filters and authentication checks to land in the inbox. Test your emails with MailMoxie before sending to identify and fix deliverability issues.
What is Email Deliverability?
Email deliverability is the ability of an email to successfully reach the recipient's inbox rather than being filtered into spam or rejected entirely. It measures how well your emails pass through spam filters and authentication checks to land in the inbox, which is different from simply being delivered to the mail server.
Quick Answer
Email deliverability is the ability of an email to successfully reach the recipient's inbox rather than being filtered into spam or rejected entirely. It measures how well your emails pass through spam filters and authentication checks to land in the inbox.
Understanding Email Deliverability
Email deliverability is a critical metric for email marketers and businesses that rely on email communication. While many people use "delivery" and "deliverability" interchangeably, they refer to different stages of the email journey.
Deliverability vs. Delivery
Email Delivery refers to whether an email was accepted by the recipient's mail server. An email can be "delivered" to the server but still end up in the spam folder.
Email Deliverability refers to whether an email successfully reaches the recipient's inbox (not spam folder) after being accepted by the mail server. This is what most email senders care about—getting messages into the inbox where recipients will see them.
Why Deliverability Matters
Poor email deliverability means your messages aren't reaching their intended audience, even if they're technically being delivered. This impacts:
- Marketing ROI: Emails in spam folders don't generate opens, clicks, or conversions
- Customer communication: Important transactional emails may be missed
- Brand reputation: Consistently poor deliverability can damage your sender reputation
- Revenue: Lower deliverability directly impacts revenue for email-dependent businesses
How Email Deliverability Works
When you send an email, it goes through multiple stages before reaching the inbox:
1. Initial Delivery
Your email service provider sends the email to the recipient's mail server (like Gmail, Outlook, Yahoo). At this stage, the server decides whether to accept or reject the email.
2. Authentication Checks
The receiving server checks your DNS records:
- SPF (Sender Policy Framework): Verifies your sending server is authorized
- DKIM (DomainKeys Identified Mail): Verifies the email hasn't been tampered with
- DMARC (Domain-based Message Authentication): Enforces authentication policies
3. Reputation Evaluation
The receiving server evaluates:
- IP reputation: History of your sending IP address
- Domain reputation: History of your sending domain
- Sender reputation: Overall sending behavior and engagement
4. Content Filtering
The server scans email content for:
- Spam trigger words and phrases
- Suspicious links or attachments
- HTML structure and formatting issues
- Image-to-text ratios
5. Engagement History
The server considers:
- Previous engagement with your emails (opens, clicks)
- Complaint rates (spam reports)
- Bounce rates (invalid addresses)
6. Final Decision
Based on all factors, the server decides:
- Inbox: Email reaches the primary inbox
- Spam folder: Email is filtered but not rejected
- Rejection: Email is bounced back (hard bounce)
Key Factors Affecting Deliverability
Technical Factors
- DNS Authentication: SPF, DKIM, and DMARC records must be properly configured
- IP Reputation: Your sending IP address's history and reputation
- Domain Reputation: Your sending domain's reputation
- Infrastructure: Email server configuration and security
Sender Reputation
- Sending history: Consistent, legitimate sending patterns
- Volume consistency: Gradual increases rather than sudden spikes
- List quality: Clean, engaged email lists
- Complaint rates: Low spam complaint rates
Content Quality
- Relevance: Content that matches recipient expectations
- Spam triggers: Avoiding words and patterns that trigger filters
- Formatting: Proper HTML structure and formatting
- Links: Reputable link destinations
Engagement Metrics
- Open rates: Higher engagement improves deliverability
- Click rates: Active engagement signals quality
- Reply rates: Two-way engagement is highly valued
- Unsubscribe rates: Low unsubscribe rates indicate relevance
Why Email Deliverability is Important
Business Impact
Revenue: For email marketing, deliverability directly impacts revenue. If emails don't reach inboxes, campaigns can't generate results.
Customer relationships: Poor deliverability means important communications (order confirmations, password resets, newsletters) may be missed.
Brand trust: Consistently landing in spam can damage brand perception and trust.
Industry Standards
Most email service providers aim for deliverability rates above 95%. However, deliverability varies by:
- Industry (some industries face stricter filtering)
- Sending volume (high-volume senders face more scrutiny)
- List quality (cleaner lists perform better)
- Engagement history (established relationships perform better)
Common Deliverability Challenges
Authentication Issues
Missing or misconfigured SPF, DKIM, or DMARC records can cause emails to be filtered or rejected. Authentication is the foundation of good deliverability.
Poor Sender Reputation
New IP addresses, sudden volume increases, or past sending issues can damage reputation. Building and maintaining reputation takes time and consistent good practices.
Low Engagement
Emails that aren't opened or clicked signal to receiving servers that recipients don't want them. This can lead to future emails being filtered.
List Quality Issues
High bounce rates, spam complaints, or inactive subscribers can hurt deliverability. Regular list hygiene is essential.
Content Problems
Spam trigger words, poor formatting, or suspicious content can cause filtering even with good authentication and reputation.
Measuring Email Deliverability
Key Metrics
- Inbox placement rate: Percentage of emails reaching the inbox
- Spam folder rate: Percentage filtered to spam
- Bounce rate: Percentage rejected by servers
- Open rate: Engagement indicator
- Click rate: Engagement indicator
Monitoring Tools
- Email service provider analytics: Built-in deliverability metrics
- DMARC reports: Authentication and delivery statistics
- Deliverability monitoring services: Third-party inbox placement testing
- Sender reputation tools: IP and domain reputation scores
Improving Email Deliverability
While deliverability involves many factors, key steps include:
- Set up authentication: Configure SPF, DKIM, and DMARC records
- Maintain clean lists: Remove bounces, handle unsubscribes, segment lists
- Send relevant content: Match recipient expectations and interests
- Monitor metrics: Track opens, clicks, bounces, and complaints
- Build reputation: Start with small volumes, gradually increase, maintain consistency
- Follow best practices: Use double opt-in, honor preferences, send at appropriate frequencies
Common Questions
Q: What's the difference between email delivery and email deliverability?
A: Email delivery means the email was accepted by the recipient's mail server. Email deliverability means the email reached the inbox (not spam folder). An email can be delivered but have poor deliverability if it lands in spam.
Q: What is a good email deliverability rate?
A: Most email service providers aim for deliverability rates above 95%, meaning 95% or more of emails reach the inbox. However, rates vary by industry, sending volume, and list quality. Focus on improving your rate over time rather than comparing to others.
Q: Can I improve deliverability quickly?
A: Some improvements are immediate (fixing authentication), while others take time (building reputation). Authentication fixes can improve deliverability within hours, but reputation building takes weeks or months of consistent good practices.
Q: Does email content affect deliverability?
A: Yes, content quality significantly affects deliverability. Spam trigger words, poor formatting, suspicious links, and low engagement can cause filtering. Relevant, well-formatted content with good engagement improves deliverability.
Q: What happens if my deliverability is poor?
A: Poor deliverability means emails land in spam folders or are rejected. This reduces opens, clicks, and conversions. Over time, poor deliverability can damage sender reputation, making it harder to reach inboxes in the future.
Q: Do I need to set up SPF, DKIM, and DMARC for good deliverability?
A: Yes, authentication is essential for good deliverability. Without proper SPF, DKIM, and DMARC records, receiving servers can't verify your emails are legitimate, leading to filtering or rejection.
Q: Can I check my email deliverability?
A: Yes, you can monitor deliverability through email service provider analytics, DMARC reports, deliverability monitoring tools, and inbox placement testing services. Regular monitoring helps identify issues early.
Q: Does sending volume affect deliverability?
A: Yes, sudden volume increases can trigger spam filters and hurt deliverability. It's important to warm up new IP addresses gradually and maintain consistent sending volumes. Established senders with good reputation can handle higher volumes.
Q: What is sender reputation?
A: Sender reputation is a score that receiving servers assign based on your sending history, including engagement rates, complaint rates, bounce rates, and authentication. Good reputation improves deliverability, while poor reputation hurts it.
Q: Can I recover from poor deliverability?
A: Yes, but it takes time and consistent good practices. Fix authentication issues immediately, clean your email list, improve content quality, reduce sending volume if needed, and gradually rebuild reputation through consistent, legitimate sending.
Key Takeaways
- Email deliverability measures whether emails reach the inbox (not spam folder), not just whether they're delivered to the server
- Deliverability is affected by authentication (SPF, DKIM, DMARC), sender reputation, content quality, and engagement rates
- Most email service providers aim for deliverability rates above 95%
- Authentication is the foundation of good deliverability—set up SPF, DKIM, and DMARC records
- Regular monitoring helps identify deliverability issues before they significantly impact campaigns
- Improving deliverability requires a combination of technical setup, list hygiene, content quality, and reputation building
- Poor deliverability directly impacts revenue, customer relationships, and brand trust