What is Email Deliverability?
Short Description:
The ability of your emails to successfully reach recipients’ inboxes rather than spam folders or being blocked entirely.
Expanded Description:
Email deliverability is a critical metric that measures the percentage of sent emails that actually reach the intended recipient’s inbox, as opposed to being filtered into spam folders, blocked by email providers, or bouncing back undelivered. Deliverability is influenced by a complex ecosystem of factors including sender reputation, email authentication protocols, content quality, recipient engagement, and list hygiene practices. Poor deliverability can devastate email marketing ROI, with some companies seeing deliverability rates as low as 60-70%, meaning nearly one-third of their messages never reach prospects. Industry best practices aim for 95%+ deliverability rates.
Key Deliverability Factors:
Technical Authentication:
- SPF (Sender Policy Framework): Validates that emails are sent from authorized servers
- DKIM (DomainKeys Identified Mail): Provides cryptographic signature to verify message authenticity
- DMARC (Domain-based Message Authentication, Reporting & Conformance): Coordinates SPF and DKIM policies
- Custom Domains: Using branded sending domains rather than shared providers
- IP Warming: Gradually establishing sending reputation for new IP addresses
Sender Reputation:
- Domain Reputation: Historical sending patterns and recipient interactions
- IP Reputation: Quality score based on sending volume and complaint rates
- Engagement Metrics: Open rates, click rates, reply rates, and time spent reading
- Complaint Rates: Spam reports and unsubscribe requests
- Bounce Management: Handling hard bounces and maintaining clean lists
Content and Design:
- Subject Line Optimization: Avoiding spam trigger words and excessive punctuation
- HTML/Text Ratio: Balanced content that renders properly across email clients
- Image Optimization: Proper alt text and avoiding image-heavy designs
- Link Quality: Using reputable domains and avoiding suspicious redirects
- Personalization: Relevant, targeted content that encourages engagement
List Quality and Management:
- Permission-Based Lists: Ensuring recipients opted in to receive communications
- Regular List Cleaning: Removing bounced emails and inactive subscribers
- Engagement Monitoring: Identifying and re-engaging or suppressing low-engagement contacts
- Compliance: Adhering to CAN-SPAM, GDPR, and other anti-spam regulations
Monitoring and Optimization:
- Deliverability Tools: Using services like Return Path, 250ok, or GlockApps
- Inbox Placement Testing: Monitoring where emails land across different providers
- Engagement Analysis: Tracking metrics that influence sender reputation
- A/B Testing: Optimizing subject lines, send times, and content for better performance
Common Deliverability Issues:
- High Bounce Rates: Often caused by outdated or purchased email lists
- Low Engagement: Results in emails being filtered to promotions or spam folders
- Authentication Failures: Technical setup issues that flag emails as suspicious
- Content Triggers: Using language or formatting that activates spam filters
- Sending Frequency: Too much or inconsistent email volume
Example:
A B2B company notices their email deliverability dropped from 94% to 78% after purchasing a large contact list. Investigation reveals high bounce rates (12%) and low engagement (2% open rate) from the purchased contacts. They implement list cleaning, remove bounced addresses, segment engaged vs. unengaged contacts, and focus outreach on verified, relevant prospects, bringing deliverability back to 96% within 30 days.