How accurate are seedlists in deliverability platforms like Everest and Glockapps?

Summary

Experts, marketers, and documentation sources agree that seed lists in deliverability platforms like Everest and Glockapps provide a limited and potentially inaccurate view of overall email deliverability. While useful for identifying major issues like blocks and spam filtering, they don't account for personalized filtering, user behavior, or engagement metrics. Seed lists should be used as a starting point and combined with other data sources such as sender reputation monitoring, real-world campaign results, and internal metrics like open and click-through rates. A holistic approach to deliverability, considering factors like content, sender reputation, authentication, and list quality, is crucial for success.

Key findings

  • Limited Accuracy: Seed lists don't perfectly mirror real-world inbox placement due to factors like personalized filtering and user behavior.
  • Directional Tool: Seed lists should be used as a directional tool for identifying potential deliverability issues, not as a definitive measure.
  • Lack Engagement Data: Seed lists don't provide insights into user engagement, which is a crucial factor in deliverability.
  • Identifiable: Mailbox providers can identify and potentially treat seed list addresses differently, impacting accuracy.
  • AI Engagement Concerns: The use of AI to simulate engagement in some seed list providers raises concerns about the reliability of the data.

Key considerations

  • Holistic Approach: Take a holistic approach to deliverability, considering all factors that impact inbox placement, including content, reputation, and authentication.
  • Data Combination: Combine seed list data with other data sources, such as sender reputation monitoring, real-world campaign results, and internal metrics.
  • Trend Analysis: Analyze trends over time rather than relying on single data points.
  • Encourage Engagement: Encourage user engagement and feedback to gain insights into how your emails are being received.
  • Baseline Establishment: Establish baseline metrics for your email program to identify deviations and potential problems.

What email marketers say
14Marketer opinions

Seed lists in deliverability platforms like Everest and Glockapps provide a snapshot of inbox placement, but their accuracy is limited. They don't fully reflect real-world user behavior, personalized filtering, or engagement metrics. While useful for initial testing and identifying major deliverability issues like blocks and spam filtering, they should be combined with other data sources, such as real-world campaign results, sender reputation monitoring, and internal metrics like open rates and click-through rates, to get a comprehensive view of deliverability. Engagement imitation is now mostly AI, potentially decreasing trend accuracy. Encouraging engagement/feedback directly from recipients is a valuable approach.

Key opinions

  • Limited Accuracy: Seed lists don't perfectly mirror real-world inbox placement due to factors like user behavior and personalized filtering.
  • Directional Tool: Seed lists should be used as directional tools rather than definitive measures of deliverability.
  • Snapshot in Time: Seed lists provide a snapshot of inbox placement at major ISPs but don't account for evolving filtering algorithms.
  • AI Engagement Concerns: Engagement imitation is now often AI-driven, potentially impacting the reliability of trend analysis.
  • Combine with Other Data: Combine seed list data with sending data, engagement metrics, and sender reputation monitoring for a complete picture.

Key considerations

  • User Engagement: Encourage user engagement and feedback directly through replies to emails for valuable insights.
  • Baseline Metrics: Establish baseline metrics to understand typical performance and identify meaningful deviations.
  • Trend Analysis: Focus on trending data over time rather than relying on single data points, which can be misleading.
  • Holistic Approach: A holistic approach considering sending infrastructure, authentication, list quality, engagement, content, and complaints is key to deliverability.
  • Pre-Send Testing: Implement pre-send testing to identify and resolve deliverability issues before impacting recipients.
Marketer view

Email marketer from StackOverflow explains that while seed lists can give a general idea, they don't account for personalized filtering. Each user's inbox is unique, and seed lists can't capture that.

February 2025 - StackOverflow
Marketer view

Email marketer from EmailVendorSelection Forum shares that seedlists can be a good starting point for testing, but you need to combine that data with your own sending data and engagement metrics to get a true picture of your deliverability.

May 2023 - EmailVendorSelection Forum
Marketer view

Email marketer from Email Geeks explains that engagement imitation was somewhat useful for seeing trends when it was actual panel data from real recipients. But, now it's all "AI", e.g. if/then statements with rand() functions.

September 2021 - Email Geeks
Marketer view

Email marketer from Email Geeks shares that when comparing client data against seedlist data, the seedlists may be more or less correct, and other times, total false negatives. Therefore, she uses these third-party tools as just a directional tool. Actual sending data is the real deal.

May 2023 - Email Geeks
Marketer view

Email marketer from Email Geeks seconds the trending of data as one blip taken by itself can be misleading, but trended over time may be just an ISP blip that resolved itself the next day.

December 2023 - Email Geeks
Marketer view

Email marketer from Litmus explains that pre-send testing helps ensure emails render correctly across different devices and clients. They also state that they can help uncover deliverability issues before they impact your customers.

July 2021 - Litmus
Marketer view

Email marketer from Reddit shares that seed lists are good for initial testing and identifying major issues, but they are not a perfect representation of deliverability for all users. They recommend using them in conjunction with other deliverability monitoring methods.

February 2023 - Reddit
Marketer view

Email marketer from EmailToolTester explains that deliverability testing tools such as GlockApps can be effective in finding whether emails are being delivered and where. They state that they deliver to seed email addresses, then tell you the folders your emails landed in, they also check for authentication issues and measure response times.

March 2022 - EmailToolTester
Marketer view

Email marketer from Mailtrap Blog explains that seed list testing, while valuable, doesn't perfectly mirror real-world inbox placement. Factors like user behavior, IP reputation, and content quality heavily influence deliverability, making seed lists just one piece of the puzzle.

April 2024 - Mailtrap Blog
Marketer view

Email marketer from Email Geeks shares that you need to create a base line so you know what a good week/month/year looks like first.

April 2022 - Email Geeks
Marketer view

Email marketer from GMass Blog shares that seed lists provide a snapshot of inbox placement at major ISPs but don't account for personalized filtering or engagement metrics. They suggest combining seed list data with real-world campaign results for a more comprehensive view.

July 2023 - GMass Blog
Marketer view

Email marketer from Validity Blog shares that deliverability is achieved when the emails sent reach the intended audience in their inboxes. They explain that there are multiple factors that impact deliverability including sending infrastructure and reputation, authentication, list quality, engagement, content, and complaints.

April 2024 - Validity Blog
Marketer view

Email marketer from Quora suggests using a combination of seed list testing and monitoring your sender reputation to get a good understanding of your deliverability. Seed lists can give you a quick snapshot, but your reputation is what matters in the long run.

June 2024 - Quora
Marketer view

Email marketer from Email Geeks shares that simplest things a marketer can do is encourage engagement/feedback by letting people reply to the emails. Have it go into a ticketing system or something but it's gold if done right.

November 2024 - Email Geeks

What the experts say
4Expert opinions

Experts agree that seed lists offer a basic method for identifying significant deliverability issues, such as blocks or spam filtering, but they are not a complete assessment of deliverability. Consumer mailbox providers don't filter mail in a way that makes seed lists as insightful as they used to be. They are limited in scope, do not accurately reflect real-world user behavior, and don't show engagement. Therefore, seed list data should be used carefully, with emphasis placed on identifying trends and putting the data into context with the rest of your email program.

Key opinions

  • Limited Accuracy: Seed lists are not a perfect reflection of real-world deliverability due to personalized filtering and other factors.
  • Basic Diagnostics: Seed lists are most useful for identifying fundamental issues like blocks or spam folder placement.
  • Lack of Engagement Data: Seed lists do not provide insights into user engagement with your emails.
  • Evolving Filtering: Consumer mailbox providers change their filtering methods, reducing the insight seed lists provide.

Key considerations

  • Trend Analysis: Focus on identifying trends in your deliverability data rather than relying on individual data points.
  • Contextualization: Interpret seed list data in the context of your overall email program and audience.
  • Holistic Assessment: Use seed lists as one component of a more comprehensive deliverability assessment strategy.
Expert view

Expert from Spamresource.com explains that seed list testing offers a straightforward way to identify significant delivery issues, such as being blocked or routed to the spam folder by specific ISPs. However, these tests do not replicate real-world user engagement or individualized filtering, thus, results should be viewed as a basic diagnostic rather than a complete assessment of deliverability.

January 2023 - Spamresource.com
Expert view

Expert from Email Geeks explains that seedlists are all mostly the same in terms of accuracy but consumer mailbox providers don’t filter mail in a way that makes seed lists as insightful as they used to be. Seedlist data should be put into context with the rest of your program as ISPs can tell what seedlist addresses are and don’t treat them the same as subscribers. The AI backed engagement is attempting to do good things, but how accurate the data can be is questionable.

October 2021 - Email Geeks
Expert view

Expert from Email Geeks recommends to always look at trends, rather than discrete data points. Look at the variations and compare it week by week.

February 2022 - Email Geeks
Expert view

Expert from Word to the Wise shares that seed list data is limited and you have to be careful. While seedlists can be useful for identifying basic delivery problems (blocks, filtering), they don't accurately reflect real-world user behavior or the impact of personalized filtering, and seedlists are limited to only a few mailboxes and they do not show you engagement.

September 2021 - Word to the Wise

What the documentation says
3Technical articles

Email deliverability platforms highlight that seed lists offer helpful insights in a controlled environment, yet they are not a complete representation of deliverability. Mailbox providers can identify seed lists, and the results may not reflect actual user behavior or personalized filtering. A comprehensive approach is required, supplementing seed list data with internal metrics like open rates, click-through rates, engagement metrics, and feedback loops to address potential delivery issues related to content, sender reputation, and authentication.

Key findings

  • Identifiable Seed Lists: Mailbox providers can often identify seed lists, impacting their accuracy.
  • Unrealistic Environment: Seed lists operate in a controlled environment that may not mirror real-world conditions.
  • Incomplete Picture: Seed lists alone do not provide a complete picture of deliverability.

Key considerations

  • Holistic Review: Review deliverability data holistically, incorporating internal data sources.
  • Supplement with Engagement: Supplement seed list results with engagement metrics and feedback loops.
  • Address Delivery Issues: Troubleshoot common deliverability issues related to content, reputation, and authentication.
Technical article

Documentation from SendGrid Documentation explains that deliverability tools using seed lists can provide helpful insight, but these lists can also be identified by mailbox providers, making it important to review deliverability data more holistically with internal data like open rates and click-through rates.

September 2024 - SendGrid Documentation
Technical article

Documentation from Mailchimp Knowledge Base explains that delivery problems occur when an email doesn't reach the intended recipient's inbox. They state that the causes of these problems include issues with content, domain, sender reputation and authentication. They suggest troubleshooting common deliverability issues to fix it.

August 2022 - Mailchimp Knowledge Base
Technical article

Documentation from SparkPost Documentation notes that seed lists provide a controlled environment for testing but might not reflect real-world user behavior or personalized filtering. They recommend supplementing seed list results with engagement metrics and feedback loops.

February 2022 - SparkPost Documentation