What are the best practices for email deliverability and avoiding spam filters?

Key findings

• No magic bullet: There is no single fix for email deliverability; it requires a holistic strategy across multiple aspects of email sending.
• Sender reputation is paramount: Maintaining a positive sender reputation is critical, as it directly influences whether emails reach the inbox or are filtered as spam.
• User engagement matters: Genuine user engagement signals, such as opens, clicks, and replies, are far more effective than artificial attempts to bypass filters.
• Spam filters evolve: Spam algorithms are increasingly sophisticated, using behavioral data and recipient feedback to refine their filtering processes.

Key considerations

• Prioritize consent: Always ensure you have explicit permission to email recipients. This builds a foundation of trust and reduces spam complaints.
• Monitor your metrics: Regularly track key deliverability metrics, such as open rates, click-through rates, bounce rates, and spam complaint rates, to identify and address issues promptly.
• Implement authentication: Properly configure authentication protocols like SPF, DKIM, and DMARC to prove your emails are legitimate. This is crucial for avoiding spam folders, especially with major providers like Gmail and Yahoo.
• Focus on content and segmentation: Send relevant content to segmented audiences to increase engagement and reduce the likelihood of recipients marking your emails as spam. More insights on this can be found in this Mailchimp guide on avoiding spam filters.
• Understand spam reasons: Emails can go to spam for various reasons, including low engagement, high complaint rates, or technical misconfigurations.

Key opinions

• Avoid spammy behavior: The most straightforward way to avoid deliverability issues is to simply not act like a spammer.
• Artificial engagement fails: Attempts to game the system, like having company employees mark emails as 'not spam,' are ineffective and won't improve inbox placement.
• Subjective spam reports: Users may mark emails as spam for reasons unrelated to actual spam, such as dissatisfaction with content or pricing, highlighting the subjective nature of spam complaints.
• Misguided IP acquisition: The belief that one can simply buy IPs with existing good reputations for easy deliverability is a common misconception.

Key considerations

• User behavior impact: Acknowledge that diverse user behavior, including incorrect spam reports or using junk folders for storage, can affect your domain reputation and deliverability.
• Focus on genuine value: The most effective strategy is to consistently send content that your subscribers genuinely want and expect.
• Reputable ESPs: Using a reputable Email Service Provider (ESP) is a foundational best practice, as they implement systems to prevent spam and help maintain good IP reputation. More details can be found in this EmailTooltester.com guide.
• Strategic 'From' addresses: Carefully choose and manage your 'From' addresses to foster trust and recognition among recipients and ISPs.

Key opinions

• No single solution: There is no magic bullet for email deliverability; it's a culmination of many factors.
• Trusted reporters: ISPs actively identify and give more weight to spam reports from 'trusted reporters,' who are accurate in their spam classifications.
• Recipient tracking: Email algorithms track recipients' behavior both individually and as part of groups, influencing sending reputation and inbox placement.
• ISP control: The impact of recipient tracking is most significant at ISPs that control both the mail client and the Mail Transfer Agent (MTA).

Key considerations

• Holistic approach: Adopt a comprehensive deliverability strategy that accounts for technical setup, content quality, sender reputation, and recipient behavior. For instance, consider implementing DMARC, SPF, and DKIM.
• Beyond bulk mail: Understand that even non-bulk emails, including personal correspondence, can be marked as spam, indicating a broader user behavior issue. This can even happen due to email backscatter.
• ISP feedback mechanisms: Be aware that some ISPs, like Hotmail, actively solicit user feedback on spam accuracy, which influences their filtering algorithms. More expert insights are available via Salesforce's email deliverability resources.

Key findings

• Authentication is essential: Compliance with SPF, DKIM, and DMARC is fundamental for senders to establish legitimacy and prevent spoofing.
• Complaint rates are critical: Maintaining a very low spam complaint rate is a key indicator of positive sender reputation and inbox placement.
• Engagement drives placement: User interaction, including opens, clicks, and not marking as spam, significantly influences how ISPs filter incoming mail.
• Permission-based lists: Building and maintaining permission-based email lists, free of invalid or unengaged addresses, is a foundational practice.

Key considerations

• DMARC policy: Implementing a robust DMARC policy beyond p=none is recommended for maximum protection and deliverability.
• List hygiene: Regularly clean your email lists to remove inactive, invalid, or problematic addresses, which can lead to high bounce rates or spam traps.
• Clear unsubscribe options: Always provide easy-to-find and functional unsubscribe links to allow users to opt-out gracefully, rather than marking emails as spam.
• Blocklist monitoring: Proactively monitor for your domain or IP being listed on email blocklists or blacklists, and take swift action if listed. Further insights from authoritative sources, such as Mailgun's deliverability blog, also underline these points.