How relevant is SpamAssassin scoring for modern email deliverability?

Summary

While SpamAssassin remains a functional tool for identifying potential spam indicators and analyzing email content, its relevance for modern email deliverability is limited. Modern email providers such as Gmail and Yahoo rely on more sophisticated algorithms that consider sender reputation, email authentication (SPF, DKIM, DMARC), user engagement, and list hygiene as primary factors for determining inbox placement. SpamAssassin scores should be seen as a starting point or one component of a broader deliverability strategy, not the sole determinant of email success. Furthermore, a small number of recipients use SpamAssassin and even scores across different versions can vary wildly.

Key findings

  • Declining Relevance: SpamAssassin's impact on deliverability has diminished due to the rise of advanced filtering techniques.
  • Modern Algorithms: Modern filters prioritize sender reputation, authentication, engagement, and list hygiene over content-based filtering alone.
  • Limited Recipient Base: Only a small percentage of email recipients rely on SpamAssassin, reducing its overall importance.
  • One Piece of the Puzzle: SpamAssassin should be considered as one part of a layered defense strategy, not the sole indicator of deliverability.
  • Version Variations: Scores can vary significantly between different versions.

Key considerations

  • Sender Reputation: Focus on building and maintaining a positive sender reputation through consistent sending practices and engagement.
  • Email Authentication: Implement SPF, DKIM, and DMARC to verify the authenticity of your emails and improve deliverability.
  • User Engagement: Encourage recipient interaction through compelling content and calls-to-action.
  • List Hygiene: Regularly clean and segment your email lists to remove inactive or unengaged subscribers.
  • Holistic Strategy: Develop a comprehensive deliverability strategy that encompasses various factors beyond just SpamAssassin scores.

What email marketers say
11Marketer opinions

While SpamAssassin can still be a useful tool for identifying potential email issues and may still be used by smaller mail servers, it is no longer a primary factor in determining email deliverability for major email providers like Gmail and Yahoo. Modern email filters rely on sophisticated algorithms that prioritize sender reputation, email authentication (SPF, DKIM, DMARC), user engagement, and list hygiene. Therefore, focusing on these areas is more crucial for achieving high deliverability rates.

Key opinions

  • Diminished Importance: SpamAssassin's relevance has decreased with the rise of sophisticated, personalized filtering algorithms.
  • Part of a Bigger Picture: SpamAssassin is only one filter among many, and passing it is not a guarantee of inbox placement.
  • Outdated Tool: SpamAssassin is an older tool compared to modern filters that incorporate machine learning and user behavior analysis.
  • Focus Shift: The emphasis has shifted from content-based filtering to sender reputation and recipient engagement.

Key considerations

  • Sender Reputation: Building and maintaining a strong sender reputation is paramount for modern email deliverability.
  • Email Authentication: Implementing SPF, DKIM, and DMARC is crucial for verifying email authenticity and improving deliverability.
  • User Engagement: Encouraging positive recipient interactions, such as opens and clicks, can significantly boost deliverability.
  • List Hygiene: Regularly cleaning email lists to remove inactive or unengaged subscribers is essential for maintaining a healthy sender reputation.
  • Comprehensive Approach: Employing a comprehensive email marketing strategy that addresses all aspects of deliverability is essential.
Marketer view

Email marketer from HubSpot.com shares that focusing on email authentication, list segmentation, and personalization efforts will have a greater impact on deliverability than just optimizing for SpamAssassin scores.

May 2023 - HubSpot.com
Marketer view

Email marketer from Email Geeks acknowledges that SpamAssassin itself does not mean everything, but is still used by personal servers or small in-house built company mail servers. It can point out obvious issues on the email structure. However, it's only an indicator and part of a global analysis.

December 2023 - Email Geeks
Marketer view

Email marketer from Litmus.com shares that while SpamAssassin can catch some issues, focusing on email authentication (SPF, DKIM, DMARC), list hygiene, and engagement metrics will have a greater impact on deliverability.

March 2022 - Litmus.com
Marketer view

Email marketer from Reddit shares that SpamAssassin's importance has diminished due to the rise of sophisticated spam filters. Now, focus on sender reputation, engagement metrics, and proper email authentication is more important.

December 2022 - Reddit
Marketer view

Email marketer from Mailjet.com shares that while SpamAssassin is a factor, modern deliverability depends on sender reputation, authentication (SPF, DKIM, DMARC), engagement, and list hygiene. SpamAssassin is just one filter among many.

October 2022 - Mailjet.com
Marketer view

Email marketer from EmailOctopus.com shares that SpamAssassin checks are a good starting point for assessing email content, but other factors like sender reputation and engagement greatly outweigh its significance in modern deliverability.

June 2023 - EmailOctopus.com
Marketer view

Email marketer from GMass.co responds that while SpamAssassin flags can provide helpful hints, real-world deliverability is heavily influenced by Google's and other ISPs' algorithms, which prioritize sender reputation and recipient interaction.

July 2023 - GMass.co
Marketer view

Email marketer from SendGrid.com responds that SpamAssassin is an older tool. Modern filters incorporate machine learning and user behavior, making SpamAssassin less determinative on its own. Strong sender reputation and authentication are more critical.

November 2024 - SendGrid.com
Marketer view

Email marketer from emailmarketingforum.com comments that SpamAssassin can be useful as an initial check but shouldn't be considered the ultimate authority on email deliverability. Modern email providers use more complex systems.

December 2021 - emailmarketingforum.com
Marketer view

Email marketer from MailerCheck.com shares that achieving a low SpamAssassin score is essential, but it's only one piece of the deliverability puzzle. Building a good sender reputation and keeping your lists clean are also extremely important.

April 2021 - MailerCheck.com
Marketer view

Email marketer from GlockApps.com responds that SpamAssassin is a general, open-source filter, while modern spam filters used by Gmail, Yahoo, etc., are far more sophisticated and personalized. Passing SpamAssassin is a minimum requirement, not a guarantee of inbox placement.

March 2024 - GlockApps.com

What the experts say
4Expert opinions

SpamAssassin's relevance for modern email deliverability is limited. While it was important historically and might still be used in some contexts, its impact has diminished as modern email providers rely more heavily on sender reputation, authentication (SPF, DKIM, DMARC), and user engagement. Furthermore, the small percentage of recipients using SpamAssassin and the variability of scores across different versions reduces its significance. Therefore, SpamAssassin should be viewed as just one piece of a larger deliverability strategy, not the sole determinant of success.

Key opinions

  • Limited Recipient Base: A small percentage of email recipients use SpamAssassin, making its impact on overall deliverability limited.
  • Version Variability: SpamAssassin scores can vary significantly depending on the version used, reducing its reliability.
  • Decreasing Influence: SpamAssassin's influence has decreased as modern email providers prioritize sender reputation and engagement.
  • Part of a Puzzle: SpamAssassin is just one component of a comprehensive deliverability strategy, not the sole factor.

Key considerations

  • Sender Reputation: Focus on building and maintaining a strong sender reputation.
  • Email Authentication: Implement SPF, DKIM, and DMARC to authenticate your emails.
  • User Engagement: Prioritize user engagement as a key factor in deliverability.
  • Comprehensive Strategy: Develop a comprehensive email marketing strategy that includes various deliverability factors, not just SpamAssassin.
Expert view

Expert from Word to the Wise responds that SpamAssassin should be seen as one part of the puzzle. Good content, sender reputation, and authentication are essential for modern deliverability. Don't rely on just one thing.

March 2023 - Word to the Wise
Expert view

Expert from Email Geeks states that the number of recipients on domains using SpamAssassin is less than 5% of a standard mailing list, making it relatively meaningless for deliverability.

January 2023 - Email Geeks
Expert view

Expert from Word to the Wise explains that while SpamAssassin was important years ago and is still used in some places, its influence has been decreasing. Factors like sender reputation, authentication (SPF, DKIM, DMARC), and engagement are now more critical.

April 2023 - Word to the Wise
Expert view

Expert from Email Geeks suggests specifying the SpamAssassin version being used, as the version number matters for scoring. She's interested in seeing results across multiple versions to demonstrate score variations. She notes that the number of recipients on domains using SpamAssassin is small and that you don’t know what version any particular recipient group is running and the scores can vary wildly from version to version

June 2022 - Email Geeks

What the documentation says
3Technical articles

SpamAssassin is a content-based spam filter employing various techniques to identify spam based on message content and headers. While it remains a useful tool for identifying spam, especially as part of a layered security approach, documentation emphasizes that relying solely on SpamAssassin is insufficient for modern email deliverability. Supplementary filtering techniques are necessary to address evolving spam tactics, positioning SpamAssassin as one component within a broader security strategy.

Key findings

  • Content-Based Filtering: SpamAssassin primarily relies on content matching and other techniques to identify spam.
  • Part of Layered Defense: It's valuable as part of a layered security approach but insufficient on its own.
  • Supplementary Techniques Needed: Modern threats require supplementary filtering techniques beyond SpamAssassin.
  • One Piece of the Puzzle: SpamAssassin is one component within a broader deliverability and security strategy.

Key considerations

  • Layered Security: Implement a layered security approach with multiple spam filtering techniques.
  • Evolving Tactics: Stay updated on evolving spam tactics and adapt filtering techniques accordingly.
  • Supplementary Filters: Utilize supplementary filtering techniques alongside SpamAssassin.
  • Comprehensive Strategy: Integrate SpamAssassin into a comprehensive email deliverability and security strategy.
Technical article

Documentation from cPanel.net describes SpamAssassin as a useful tool for identifying spam, but highlights the need for supplementary filtering techniques to address evolving spam tactics. It's one piece of the puzzle.

April 2023 - cPanel.net
Technical article

Documentation from MDaemon.com explains how to configure SpamAssassin, it acknowledges its value as part of a layered defense. However, also notes that relying solely on SpamAssassin is insufficient for modern threats. It should be used in conjunction with other security measures.

January 2025 - MDaemon.com
Technical article

Documentation from Apache.org explains that SpamAssassin is an email spam filter based on content matching, DNS-based and collaborative filtering databases, and other advanced techniques. It aims to identify spam based on message content and headers.

March 2024 - Apache.org