Deliverability is a measure of the overall health of your email marketing program. It represents both your gateway to consumer engagement and your opportunity to build stronger, more meaningful relationships through better practices and relevant content.
The Deliverability Challenge Intensifies
Reaching the inbox is more challenging than ever. Economic uncertainty, privacy laws, shifting consumer behaviors, and rapidly evolving technology make it harder for senders to connect with their audiences. Mailbox providers (MBPs) are implementing more sophisticated filtering mechanisms to protect their users from unwanted messages.
Multiple factors impact your email deliverability, including your sender reputation, authentication infrastructure, and elements of your email marketing strategy—like your sending cadence, list quality, and overall engagement.
This means that marketers must be more strategic and thoughtful about their email practices to maintain strong deliverability rates.
The 2025 Email Deliverability Benchmark Report shows:
One in six legitimate marketing emails fails to reach the inbox. This statistic represents a significant challenge for marketing ROI, as approximately 16.7% of campaigns never reach their intended audience.
Global spam placement rates almost doubled from Q1-Q4 2024. This dramatic increase suggests that MBPs have tightened their filtering criteria, making it essential for marketers to reassess their sending practices and content strategies.
Microsoft has made significant changes to filtering and emerges as the most challenging MBP for deliverability. With inbox placement rates of just 75.6 percent, Microsoft’s ecosystem requires special attention from marketers looking to reach business and consumer audiences effectively.
Regional variations reveal optimization opportunities. Europe leads global performance with inbox placement rates of 89.1 percent, suggesting that compliance with stricter privacy regulations (like GDPR) may improve deliverability outcomes.
AI creates unexpected deliverability challenges. As artificial intelligence becomes more prevalent in content creation, MBPs are developing more sophisticated detection methods that may inadvertently flag legitimate AI-generated content.
Gmail’s surprising decline demands attention. Despite accounting for nearly 50% of consumer mailboxes globally, Gmail showed an unexpected deliverability decline of almost five percent, making optimization for this platform more critical than ever.
Double opt-in markets outperform single opt-in. The US shows inbox placement rates six percentage points lower than select countries requiring double opt-in methods, highlighting the long-term benefits of stricter list-building practices.
Understanding Email Deliverability
Emails can land in several places—the inbox, the spam folder, or be blocked at MBP gateways before reaching the recipient. Most Email Service Providers (ESPs) still report delivery using a simple “sent minus bounced” equation. Since global bounce rates for permission-based email marketing hover around 1.5 percent, delivery is often reported at 98.5%. However, this metric only tells you how many emails were accepted by the receiving server, not whether they reached the inbox or were filtered into spam folders.
This distinction is crucial for measuring true campaign effectiveness. An email that reaches the spam folder has technically been “delivered” according to traditional metrics, but it has virtually no chance of being seen or acted upon by the recipient.
The Three Categories of Email Deliverability
Successful email deliverability rests on three fundamental categories:
1. Sender Reputation
Your sender reputation acts as your digital credibility score with MBPs. If you have a history of sending spam, generating complaints, or triggering spam traps, email providers are more likely to filter your emails into spam folders or block them entirely. This reputation is built over time through consistent sending practices, engagement rates, and complaint management.
2. Technical Infrastructure
Proper email authentication serves as your technical passport to the inbox. Without correctly configured SPF, DKIM, and DMARC records, your emails may be treated with suspicion or rejected outright.
3. Content and Strategy
Even with perfect reputation and technical setup, emails with inappropriate content, poor engagement patterns, or misaligned sending strategies will struggle to reach the inbox. Content quality, relevance, and subscriber engagement all play crucial roles in deliverability success.
Deliverability Optimization Strategies
Database Hygiene and List Management
Regular database cleansing and validation is required to keep your email lists up-to-date and deliverable.
- Remove inactive and improper addresses, improving your sender reputation.
- Implement sophisticated segmentation in your database to identify, manage, and target your customers and prospects.
- Create re-engagement campaigns for declining segments before removing them entirely.
- Use suppression files not just for deceased individuals, but also for complainers, hard bounces, and consistently unengaged subscribers.
Authentication and Technical Excellence
Complete your email authentication setup with properly configured SPF, DKIM, and DMARC records. Consider implementing BIMI (Brand Indicators for Message Identification) to enhance brand recognition in supported email clients. Monitor your technical setup regularly, as changes to your infrastructure or domain can impact authentication.
Content Optimization for Modern Filters
Avoid complex HTML structures that may trigger filtering algorithms. Instead, focus on clean, accessible code that renders consistently across all devices and email clients. Ensure your subject lines accurately reflect your email content, as misalignment between subject and body content is a common spam trigger.
Strategic Sending Practices
Implement IP warming protocols when changing providers or adding new IP addresses. Use dedicated IP addresses for higher volume sending to maintain better control over your sender reputation. Segment your database for targeted sending that improves engagement rates and reduces the risk of spam complaints.
Personalization and Engagement
Move beyond basic name personalization to create truly relevant content based on subscriber behavior, preferences, and lifecycle stage. Higher engagement rates signal to MBPs that your emails are wanted and valuable, improving your overall deliverability.
Conclusion
As privacy regulations continue to evolve and AI becomes more sophisticated, marketers must adapt their email strategies with stricter opt-in requirements. The most successful organizations will be those that prioritize customer experience, maintain technical excellence, and continuously monitor and optimize their deliverability performance.
About Anchor
Anchor, a leader in marketing data services, provides cost-effective end-to-end email management solutions that ensure your campaigns connect with the right audience at the right organizations.
What separates our email deployment services from the rest?
- Our opt-in email consumer database is one of the largest and most accurate in the industry with over 2.5 billion+
- The 4-step hygiene/verification process improves ISP relationships, sender reputation, deliverability, and recovers lost email addresses
- Demographic data enhancement allows targeted and personalized email communications
- We utilize your current email address to determine if a new email address is available
To learn more about how Anchor helps businesses maximize email campaign metrics while providing lists, data hygiene and validation, execution, and compliance contact:
Steve Stolls, Senior Vice President
steve@anchorcomputer.com
631-306-9301