What are the best resources for learning about email deliverability?

Summary

Learning about email deliverability requires a multi-faceted approach involving technical knowledge, proactive management, and continuous monitoring. Key resources include industry blogs, documentation from ISPs (Google, Microsoft), RFC standards, deliverability platforms (Mailchimp, Sendinblue, Litmus, Validity, GMass, SparkPost, HubSpot), community forums, and expert opinions. Core concepts revolve around authentication (SPF, DKIM, DMARC), list hygiene (removing unengaged users, avoiding spam traps), sender reputation, subscriber engagement, and understanding the email ecosystem. Tools for monitoring reputation, feedback loops with ISPs, and regular deliverability audits are also crucial.

Key findings

  • Authentication is Paramount: Implementing SPF, DKIM, and DMARC is essential for verifying sender identity and improving inbox placement.
  • List Hygiene is Non-Negotiable: Regularly cleaning email lists to remove unengaged subscribers, invalid addresses, and spam traps is critical.
  • Engagement Drives Deliverability: Consistent engagement (opens, clicks) signals positive sender reputation and improves deliverability.
  • Sender Reputation Matters: Maintaining a positive sender reputation is vital for consistent inbox placement; monitor blocklists and spam complaints.
  • Comprehensive Monitoring is Key: Utilize tools to monitor sender reputation, blocklist status, and spam complaints for proactive management.

Key considerations

  • Dedicated IP vs. Shared IP: Consider using a dedicated IP address, especially for high-volume sending, to manage your own reputation.
  • Feedback Loops (FBLs): Implement feedback loops with ISPs to identify and remove users marking messages as spam.
  • Deliverability Audits: Conduct regular deliverability audits to identify and address potential issues affecting inbox placement.
  • Email Ecosystem Understanding: Develop a comprehensive understanding of the technical and operational aspects of the email ecosystem.
  • Timeframes for List Cleaning: Understand that ideal timeframes for list cleaning vary and depend on specific business needs and deliverability goals.
  • Three week rule: Allow three weeks to improve your Google reputation.

What email marketers say
13Marketer opinions

Learning about email deliverability involves understanding a complex ecosystem and adopting a multifaceted approach. Key resources include technical documentation on authentication methods (SPF, DKIM, DMARC), industry blogs and websites, deliverability platforms, and community forums. Maintaining good deliverability requires focusing on sender reputation, list hygiene (removing unengaged subscribers and avoiding spam traps), engaging content, and monitoring key metrics like bounce rates and spam complaints. Dedicated IP addresses, feedback loops with ISPs, and deliverability audits are also important considerations.

Key opinions

  • Authentication is Key: SPF, DKIM, and DMARC are essential for verifying sender identity and improving deliverability.
  • List Hygiene Matters: Regularly cleaning your email lists to remove unengaged subscribers and avoiding purchased lists is crucial.
  • Engagement Drives Deliverability: Consistent engagement (opens, clicks) is a key factor in maintaining a good sender reputation.
  • Monitoring is Essential: Tools are needed to monitor sender reputation, blocklist status, and spam complaints.
  • Content Quality Impacts Deliverability: Creating engaging and relevant content helps maintain good sender reputation.

Key considerations

  • Dedicated IP vs Shared IP: Consider using a dedicated IP address, especially for high-volume senders, to build a unique reputation.
  • Feedback Loops (FBLs): Set up feedback loops with ISPs to be notified of spam complaints and remove those subscribers.
  • Deliverability Audits: Conduct regular deliverability audits to identify and fix issues affecting inbox placement.
  • Spam Traps: Be aware of spam traps and take steps to avoid them, such as using double opt-in.
  • Warming Up IPs: When starting with a new IP address, especially for cold email, gradually increase sending volume.
Marketer view

Email marketer from Email on Acid explains the need to use tools to monitor your sender reputation, blocklist status, and spam complaints. Also they suggest setting up feedback loops with ISPs to be notified of issues.

December 2024 - Email on Acid
Marketer view

Email marketer from Email Marketing Forum suggests that using a dedicated IP address can help improve deliverability, especially for high-volume senders, as it allows you to build your own reputation separate from shared IPs.

December 2021 - Email Marketing Forum
Marketer view

Email marketer from Email Geeks shares podcasts to learn about the topic, including: Email After Hours, Email's Not Dead, Humans of Email, Inboxing, and Email Einstein. Mentions cmswire.com, isipp.com, wordtothewise.com, and Validity's State of Email webinar series as interesting content sources.

October 2021 - Email Geeks
Marketer view

Email marketer from Email Geeks shares additional resources, including learndmarc.com, the deliverability track on InboxExpo, and a talk on March 22nd.

January 2023 - Email Geeks
Marketer view

Email marketer from Reddit explains that deliverability is a complex issue requiring a multi-faceted approach. Highlights the importance of list quality, sender reputation, proper authentication, and engaging content.

May 2023 - Reddit
Marketer view

Email marketer from Email Geeks mentions that Validity has a lot of 250ok old resources migrated to them and have generally good content. Sparkpost and salesforce also have similar level articles that are helpful.

September 2024 - Email Geeks
Marketer view

Email marketer from Mailchimp explains that deliverability depends on authentication (SPF, DKIM, DMARC), sender reputation, content quality, and subscriber engagement. They recommend focusing on building a clean list and creating engaging content.

April 2024 - Mailchimp
Marketer view

Email marketer from GMass focuses on deliverability advice specifically for cold email. They recommend warming up your sending IP address, authenticating your emails with SPF, DKIM, and DMARC, and testing your email content.

September 2023 - GMass
Marketer view

Email marketer from HubSpot explains that high bounce rates negatively impact deliverability. Advises regularly cleaning your email list to remove invalid or inactive email addresses to reduce bounce rates.

February 2025 - HubSpot
Marketer view

Email marketer from Litmus advises performing deliverability audits to identify and fix issues affecting inbox placement. Audits should include a review of authentication, sender reputation, and list hygiene practices.

April 2024 - Litmus
Marketer view

Email marketer from Sendinblue recommends several steps to improve deliverability: verifying your sender email and domain, segmenting your email lists, cleaning your email lists regularly to remove unengaged subscribers, warming up your IP address and using a dedicated IP, and monitoring your sender reputation.

April 2022 - Sendinblue
Marketer view

Email marketer from SparkPost notes that consistent engagement (opens, clicks) is crucial for maintaining good deliverability. They recommend segmenting and targeting subscribers based on their engagement levels.

December 2021 - SparkPost
Marketer view

Email marketer from Validity warns about the dangers of spam traps and how they can negatively impact sender reputation. They advise using double opt-in, regularly cleaning your lists, and avoiding purchased lists.

September 2022 - Validity

What the experts say
6Expert opinions

Learning about email deliverability involves gaining a deep understanding of the email ecosystem, including technical aspects like IP addresses, authentication protocols (SPF, DKIM, DMARC, BIMI), and reputation management. Key resources include industry blogs, RFC standards, ISP guidelines, and MAAWG best practices. Proactive management is crucial, with emphasis on list hygiene through feedback loops and understanding timeframes for list cleaning. Improving Google reputation takes at least 3 weeks.

Key opinions

  • Ecosystem Knowledge: A comprehensive understanding of the email ecosystem, including technical aspects, is essential for deliverability.
  • Resource Variety: A wide range of resources, from blogs to RFCs, is available for learning about deliverability.
  • Feedback Loops: Utilizing feedback loops (FBLs) is crucial for identifying and removing users who mark messages as spam.
  • Proactive Approach: Maintaining a proactive approach to email program health, including regular monitoring and addressing issues promptly, is vital.

Key considerations

  • List Cleaning Timeframes: Timeframes for cleaning email lists are not fixed and depend on business needs and deliverability goals.
  • Reputation Improvement: Allow at least 3 weeks to see improvements in Google reputation after making changes to sending practices.
  • Command Line Tools: Familiarize yourself with command-line tools to deep dive into the email ecosystem and troubleshooting issues.
Expert view

Expert from Spam Resource explains that a deep understanding of the entire email ecosystem is essential for deliverability. This includes areas like IP addresses, reverse DNS, email authentication, reputation, blocklists, complaint loops, and more. A deliverability professional should be well-versed in these technical aspects.

December 2022 - Spam Resource
Expert view

Expert from Email Geeks explains that time frames for cleaning email lists are arbitrary and depend on balancing business needs with deliverability. Sometimes 18 months works, sometimes 2 weeks works.

May 2024 - Email Geeks
Expert view

Expert from Email Geeks shares multiple resources for deliverability knowledge: Al’s Spamresource, Kickbox, Matt V’s emailkarma, Spamhaus blog, and her own blog Word to the Wise. Recommends MAAWG best practice documents, paying attention to spam filters, exploring anti-spam and email research, and using command line tools like dig, host, swaks, and netcat/nc. Also advises reading RFCs related to SMTP, DKIM, SPF, DMARC and BIMI. Suggests learning by reading court documents related to ISPs and spammers, postmaster blogs, and keeping up with benchmarks and white papers.

January 2024 - Email Geeks
Expert view

Expert from Word to the Wise shares the importance of Feedback Loops (FBLs) as a direct line of communication from ISPs. By signing up for FBLs, email senders can identify and remove users who mark their messages as spam, which significantly enhances deliverability and protects their sending reputation. This proactive approach is crucial for maintaining a clean and engaged email list.

November 2022 - Word to the Wise
Expert view

Expert from Email Geeks explains that Google takes at least 3 weeks to improve reputation.

September 2022 - Email Geeks
Expert view

Expert from Word to the Wise shares that understanding of RFC standards, ISPs guidelines (Gmail, Outlook etc) and having a proactive approach towards maintaining the health of the email program is crucial for email deliverability.

March 2024 - Word to the Wise

What the documentation says
5Technical articles

Learning about email deliverability from a technical documentation perspective emphasizes the importance of adhering to established protocols and guidelines. Google and Microsoft provide specific instructions for bulk email senders to improve deliverability to their respective email platforms, focusing on authentication, list management, and spam complaint handling. RFCs (Request for Comments) define the core technical standards of email, such as SMTP, while resources like dmarc.org and IETF detail how to implement specific email authentication mechanisms like DMARC and DKIM to protect against spoofing and ensure message integrity.

Key findings

  • Authentication is Critical: Implementing SPF, DKIM, and DMARC is vital for verifying sender identity and preventing email spoofing.
  • ISPs Provide Guidance: Email providers like Google and Microsoft offer specific guidelines for senders to improve deliverability to their platforms.
  • Standards Define Protocols: RFCs (Request for Comments) establish the technical foundation for email protocols like SMTP.
  • List Management is Essential: Proper list management, including confirmed opt-in and easy unsubscribe options, is a core requirement for deliverability.

Key considerations

  • Technical Implementation: Implementing email authentication protocols (SPF, DKIM, DMARC) requires technical expertise and careful configuration.
  • ISP Compliance: Adhering to the specific guidelines provided by major ISPs like Google and Microsoft is crucial for inbox placement.
  • Protocol Understanding: A foundational understanding of email protocols (e.g., SMTP) is necessary for troubleshooting deliverability issues.
  • Dynamic Evolution: Email standards and best practices evolve continuously, requiring ongoing attention and adaptation.
Technical article

Documentation from RFC explains the Simple Mail Transfer Protocol (SMTP). This document is the defining technical specification for email delivery across the internet. Provides a comprehensive guide to the protocol.

November 2021 - RFC
Technical article

Documentation from dmarc.org details how to implement DMARC (Domain-based Message Authentication, Reporting & Conformance) to protect your domain from email spoofing and phishing attacks. Provides guidance on creating and publishing DMARC records.

December 2024 - dmarc.org
Technical article

Documentation from IETF describes the DomainKeys Identified Mail (DKIM) Signatures protocol, which allows email senders to cryptographically sign their messages, verifying the message's authenticity and integrity to receiving mail servers.

August 2024 - IETF
Technical article

Documentation from Microsoft outlines guidelines for senders to improve deliverability to Outlook.com and Hotmail. It covers topics like authentication, list hygiene, and feedback loops. Provides the Sender Support form for assistance.

November 2022 - Microsoft
Technical article

Documentation from Google Support details best practices for bulk email senders, including authentication, list management, and spam complaint handling. They emphasize the importance of using a confirmed opt-in process and providing easy unsubscribe options.

June 2021 - Google Support