What resources and skills are recommended for deliverability optimization?

Summary

Optimizing email deliverability is a multi-faceted process that requires a blend of technical expertise, proactive monitoring, and continuous learning. Key findings highlight the importance of strong email authentication (SPF, DKIM, DMARC), managing sender reputation, maintaining clean email lists (list hygiene), and actively monitoring engagement metrics. Utilizing resources such as Google Postmaster Tools, feedback loops (FBLs), and understanding bounce codes are crucial. Strategies such as warming up IP addresses, A/B testing, and list segmentation can enhance deliverability. A technical foundation, staying updated with best practices, and adhering to sending limits set by providers (e.g., Microsoft) are essential considerations.

Key findings

  • Authentication: SPF, DKIM, and DMARC are crucial for verifying sender identity and preventing spoofing.
  • Sender Reputation: Maintaining a positive sender reputation is essential for avoiding spam filters.
  • List Hygiene: Regularly cleaning email lists improves engagement and reduces bounce rates.
  • Engagement Metrics: Monitoring open rates, click-through rates, and spam complaints provides insights into deliverability.
  • IP Warming: Gradually increasing sending volume for new IPs establishes a positive reputation.
  • A/B Testing: Testing different email elements optimizes engagement and reduces spam flags.
  • Segmentation: Targeting emails based on subscriber behavior and demographics improves relevance.
  • Feedback Loops (FBLs): Using FBLs to identify and remove subscribers who mark emails as spam enhances sender reputation.
  • Google Postmaster Tools: This tool is helpful for monitoring domain reputation, spam rates, and authentication issues.
  • Email metrics: Understanding email metrics like bounce rates, complaint rates, and engagement rates helps to identify deliverability problems.
  • Recipient and sender limits: Vendor specific limits on senders and recipients limits the amount of sends.

Key considerations

  • Technical Skills: A solid understanding of SMTP, DNS, email headers, and authentication protocols is necessary.
  • Continuous Learning: Staying informed about the latest deliverability best practices is essential.
  • Proactive Monitoring: Regularly monitoring sender reputation and email metrics allows for quick issue resolution.
  • Content Quality: Creating high-quality, engaging content reduces spam complaints.
  • Consistent Sending: Maintaining a consistent sending volume avoids triggering spam filters.
  • Vendor limits: Being aware of limitations for each ESP to help control sending.

What email marketers say
10Marketer opinions

Improving email deliverability requires a multifaceted approach encompassing technical skills, continuous learning, and proactive monitoring. Key areas include understanding email authentication (SPF, DKIM, DMARC), sender reputation, list hygiene, and engagement metrics. Actively reading deliverability resources, warming IP addresses, and A/B testing are beneficial. Employing dedicated tools like Google Postmaster Tools and setting up feedback loops are also essential. List segmentation based on engagement and demographic data to ensure emails are targeted and relevant to the recipient.

Key opinions

  • Authentication: Implementing and maintaining SPF, DKIM, and DMARC is crucial for verifying sender identity and preventing spoofing.
  • Sender Reputation: Sender reputation is a key factor influencing deliverability, requiring monitoring and proactive management.
  • List Hygiene: Regularly cleaning email lists by removing inactive subscribers and managing bounce rates is essential.
  • Engagement Metrics: Monitoring engagement metrics like open rates, click-through rates, and spam complaints helps identify and address deliverability issues.
  • IP Warming: Gradually warming up new IP addresses by sending low volumes of email initially helps establish a positive sending reputation.
  • A/B Testing: A/B testing various email elements to optimize engagement and reduce spam complaints is beneficial.
  • Segmentation: Segmenting email lists based on engagement, demographic, and behavioral data to personalize sending and improve deliverability.
  • Bounce codes: Understanding email bounce codes to determine if emails are hard bounces, soft bounces and what to do to address these issues.
  • Dedicated IPs: Dedicated IPs provide full control over sender reputation.

Key considerations

  • Technical Skills: A solid technical foundation in SMTP, DNS, and email header analysis is valuable for troubleshooting deliverability issues.
  • Continuous Learning: Staying updated with the latest deliverability best practices through blogs, forums, and industry resources is important.
  • Proactive Monitoring: Regularly monitoring sender reputation, bounce rates, and spam complaints is necessary to identify and address potential problems promptly.
  • Subscriber Engagement: Focus on creating high-quality content that encourages subscriber engagement to reduce spam complaints and improve deliverability.
  • Feedback Loops: Setting up and monitoring feedback loops to identify subscribers marking emails as spam and remove them from the list.
  • Sending volume: Consistent sending volume that doesn't dramatically change to avoid triggering spam filters.
Marketer view

Email marketer from SendGrid shares that improving email deliverability involves using a dedicated IP address, warming up the IP address, authenticating your email (SPF, DKIM, DMARC), segmenting your lists, and monitoring your sender reputation using tools like Google Postmaster Tools.

May 2021 - SendGrid
Marketer view

Marketer from Email Geeks advises to focus on reading and hands-on learning for deliverability optimization. He recommends blogs such as Word to the Wise, Spam Resource, and Kickbox. He also recommends <https://emailresourc.es/#|https://emailresourc.es/#>

July 2022 - Email Geeks
Marketer view

Email marketer from Stack Overflow explains the importance of understanding email bounce codes (e.g., hard bounces, soft bounces) to identify and address deliverability issues. They also explain hard bounces indicate permanent delivery failures, while soft bounces indicate temporary issues.

November 2021 - Stack Overflow
Marketer view

Email marketer from Mailchimp explains that understanding email deliverability requires considering sender reputation, authentication, content quality, and subscriber engagement. They also emphasize the importance of list hygiene and avoiding spam triggers.

June 2021 - Mailchimp
Marketer view

Email marketer from Reddit responds suggesting that warming IPs is best done by starting with low volumes of email (e.g., 500 emails/day) and gradually increasing the volume over several weeks. Also maintain a good reputation by sending to engaged subscribers and monitoring bounce rates.

December 2021 - Reddit
Marketer view

Email marketer from ReturnPath shares the best approach for list segmentation involves grouping subscribers based on demographics, behavior, and engagement levels to send more targeted and relevant emails. They also emphasize that better targeting improves engagement and reduces the likelihood of spam complaints.

February 2022 - ReturnPath
Marketer view

Email marketer from HubSpot emphasizes that key deliverability factors include sender reputation, spam complaints, email authentication (SPF, DKIM, DMARC), list hygiene (removing inactive subscribers), and consistent sending volume. They also suggest monitoring bounce rates and unsubscribe rates.

October 2021 - HubSpot
Marketer view

Marketer from Email Geeks suggests that having a technical foundation, including knowledge of SMTP, email authentication, DNS, and how to read email headers, can help learn a lot about deliverability from blogs and the Email Geeks group.

May 2023 - Email Geeks
Marketer view

Email marketer from EmailGeek Forums responds sharing that implementing email authentication protocols such as SPF, DKIM, and DMARC is crucial for improving deliverability by verifying the sender's identity and preventing spoofing. They suggest regularly checking authentication records and monitoring DMARC reports.

August 2022 - EmailGeek Forums
Marketer view

Email marketer from Litmus shares that a great way to improve deliverability is by A/B testing different elements of your email campaigns, such as subject lines, content, and sending times, to optimize engagement and reduce spam complaints. They recommend analyzing the results and iterating on your approach.

February 2022 - Litmus

What the experts say
3Expert opinions

Optimizing email deliverability hinges on three crucial elements: utilizing feedback loops (FBLs) to manage spam complaints, mastering email authentication methods (SPF, DKIM, DMARC) to validate sender legitimacy, and diligently monitoring email metrics (bounce rates, complaint rates, engagement rates) to proactively address issues affecting sending reputation and deliverability.

Key opinions

  • Feedback Loops (FBLs): FBLs are essential for identifying and removing subscribers who mark emails as spam.
  • Email Authentication (SPF, DKIM, DMARC): Proper implementation of SPF, DKIM, and DMARC is critical for preventing email spoofing and enhancing sender reputation.
  • Email Metrics: Regular monitoring of bounce rates, complaint rates, and engagement rates helps identify and resolve deliverability issues.

Key considerations

  • FBL Implementation: Setting up and actively monitoring FBLs requires technical understanding and consistent effort.
  • Authentication Expertise: Implementing email authentication requires a solid understanding of SPF, DKIM, and DMARC protocols.
  • Metric Analysis: Accurately interpreting email metrics requires expertise in data analysis and deliverability best practices.
Expert view

Expert from Word to the Wise explains that feedback loops (FBLs) are an essential resource for deliverability optimization because they provide data on spam complaints. Setting up and monitoring FBLs allows senders to identify and remove subscribers who are marking their messages as spam, improving sender reputation.

March 2025 - Word to the Wise
Expert view

Expert from Spam Resource emphasizes that understanding and implementing email authentication methods like SPF, DKIM, and DMARC is a crucial skill for deliverability optimization. Correct authentication helps establish sender legitimacy and reduces the risk of emails being filtered as spam.

March 2023 - Spam Resource
Expert view

Expert from Word to the Wise explains that understanding email metrics (bounce rates, complaint rates, engagement rates) is a critical skill for deliverability optimization. Monitoring these metrics allows senders to identify and address issues impacting their sending reputation and deliverability.

January 2025 - Word to the Wise

What the documentation says
5Technical articles

Email deliverability optimization involves understanding and implementing various technical protocols and monitoring tools. Key resources include Google Postmaster Tools for assessing domain reputation and authentication status, RFC specifications for SPF implementation, DKIM documentation for understanding email signing, and DMARC.org for implementing DMARC policies and monitoring email authentication performance. Furthermore, understanding sender and recipient limits, as defined by providers such as Microsoft, is critical to avoid deliverability issues.

Key findings

  • Google Postmaster Tools: Provides insights into domain reputation, spam rates, and authentication status specifically for Gmail users.
  • SPF: Allows domain owners to specify authorized mail servers to prevent email spoofing.
  • DKIM: Uses cryptographic signatures to verify sender identity and message integrity, protecting against tampering and phishing.
  • DMARC: Builds upon SPF and DKIM, providing control over how receivers handle authentication failures and offering reporting mechanisms.
  • Sender/Recipient Limits: Adhering to sender and recipient limits imposed by email providers is crucial for avoiding deliverability penalties.

Key considerations

  • Technical Expertise: Implementing SPF, DKIM, and DMARC requires technical knowledge of DNS records and email protocols.
  • Continuous Monitoring: Regularly monitoring Google Postmaster Tools and DMARC reports is necessary to identify and address deliverability issues promptly.
  • Policy Enforcement: Establishing and enforcing appropriate DMARC policies is critical for protecting against email spoofing.
  • Vendor limits: Understanding that each vendor has different limits and sending limits and that you should understand the vendor's documentation.
Technical article

Documentation from Google Postmaster Tools explains how to use the platform to monitor your domain reputation, spam rate, feedback loop, and authentication status. It helps identify potential issues impacting deliverability to Gmail users.

September 2023 - Google
Technical article

Documentation from DKIM explains that DKIM (DomainKeys Identified Mail) is an email authentication method that uses cryptographic signatures to verify the sender and integrity of an email message. This helps prevent email tampering and phishing attacks.

October 2021 - DKIM.org
Technical article

Documentation from DMARC.org defines DMARC (Domain-based Message Authentication, Reporting & Conformance) as an email authentication protocol that builds upon SPF and DKIM to provide domain owners with control over how email receivers handle messages that fail authentication checks. It also provides reporting mechanisms to monitor email authentication performance.

January 2025 - DMARC.org
Technical article

Documentation from Microsoft defines that understanding the limits around senders and recipents is critical for successful deliverability. Limits include the number of recipients per message, messages per day, and the rate at which messages are sent. These limits can impact deliverability if exceeded.

November 2024 - Microsoft
Technical article

Documentation from RFC Editor explains that SPF (Sender Policy Framework) is an email authentication method that helps prevent email spoofing by allowing domain owners to specify which mail servers are authorized to send email on behalf of their domain.

March 2022 - RFC Editor