How do seedlists generally work in deliverability platforms?

Seedlists work by sending a test email to a curated list of email addresses across various ISPs and mailbox providers. The platform then tracks where the email lands (inbox, spam, or blocked) for each address, providing a report on deliverability performance. Some platforms also simulate user engagement to try and mimic real-world scenarios.

Are seedlists from Everest and Glockapps perfectly accurate?

While seedlists offer valuable insights, their accuracy isn't absolute. ISPs use dynamic, personalized filtering algorithms that can often identify seedlist addresses, leading to results that might not perfectly mirror real subscriber inbox placement. Factors like sender reputation and individual user engagement heavily influence actual deliverability. To understand the full picture, you need to know how reliable email deliverability data is from seed lists .

What is 'engagement imitation' in seedlists and how does it affect accuracy?

Platforms like Everest incorporate engagement imitation, where seedlist addresses are programmed to simulate actions like opening emails or clicking links. This aims to provide more realistic deliverability results by influencing ISP filters, which often prioritize engaged senders.

How can I get a more accurate picture of my email deliverability?

To get a more accurate view, combine seedlist data with real-world engagement metrics from your ESP (opens, clicks, complaints), and direct feedback from Postmaster Tools (Google, Microsoft). Focus on trends over time rather than isolated test results. You can also monitor your blocklist monitoring data, as being listed on a blocklist (or blacklist) will significantly impact deliverability.

What factors influence real-world inbox placement beyond seedlist testing?

Maintaining a clean email list, sending relevant and valuable content, and encouraging positive engagement from your subscribers are crucial. Also, ensure your email authentication (SPF, DKIM, DMARC) records are correctly configured and monitored, as these build trust with mailbox providers.

How accurate are seedlists in deliverability platforms like Everest and Glockapps? - Tools - Email deliverability - Knowledge base

When delving into email deliverability, a common question arises regarding the accuracy of seedlists used by platforms like Everest and Glockapps. It's a valid concern, as these tools are often our first line of defense in understanding where our emails are landing. The short answer to their accuracy is, it's complicated. They offer valuable insights, but they aren't a perfect mirror of real-world inbox placement.

The effectiveness of these platforms hinges on their seedlist methodology. Some, like Everest, incorporate engagement imitation, aiming to replicate how real users interact with emails. Others, such as Glockapps, might use more straightforward seedlists without simulated engagement. This difference in approach can lead to varied results and interpretations, influencing how reliable the data appears.

Understanding seedlist mechanisms

Seedlists are a collection of email addresses across various internet service providers (ISPs) and mailbox providers, used to test where an email lands. When you send a test email to a seedlist, the platform monitors its delivery to each address, reporting whether it reached the inbox, spam folder, or was blocked. This provides a snapshot of your email's placement across different environments.

Some advanced deliverability platforms attempt to enhance seedlist accuracy by integrating "engagement imitation." This means the seedlist addresses are programmed to mimic human behavior, such as opening emails, clicking links, or marking emails as not spam. The idea is that these simulated positive interactions will influence ISP filters, providing a more realistic deliverability outcome, as real-world inbox placement is heavily influenced by recipient engagement. You can learn more about this in our article on how deliverability seed list tools function.

While engagement imitation is well-intentioned, its effectiveness is debatable. ISPs are highly sophisticated and constantly evolve their filtering algorithms. They can often identify seedlist addresses, regardless of any simulated engagement. This means emails sent to seedlists might not always be treated identically to emails sent to genuine subscribers, affecting the perceived accuracy of the results. This is especially true for free consumer mailbox providers, which filter mail in highly personalized ways.

Simple seedlists

Method: These send emails to static lists of test addresses.
Cost: Generally more affordable.
Accuracy: Provides a baseline, but can be less reflective of real-world scenarios due to lack of engagement mimicry.
Use case: Good for quick checks and identifying major blockages (or blacklists).

Engagement-imitating seedlists

Method: These use complex algorithms and sometimes panel data to simulate recipient engagement (opens, clicks, etc.).
Cost: Typically more expensive due to the advanced technology and data involved.
Accuracy: Aims for higher realism, but still subject to ISP detection and inherent limitations of simulated behavior. Why do seed list deliverability results differ from organic data?
Use case: For more nuanced insights into reputation and filtering, especially in complex email programs.

The limitations of seedlist testing

The primary limitation of seedlists stems from how mailbox providers filter emails. Their algorithms are highly dynamic and personalized, influenced by individual user behavior, past interactions, and a vast array of real-time signals. A seedlist, by its nature, cannot perfectly replicate the organic engagement patterns of a diverse subscriber base.

Many ISPs are aware of seedlist addresses and may treat them differently than genuine subscriber emails. This means that a test email sent to a seedlist might bypass certain filtering layers that a real marketing email would encounter. This disparity can lead to what we call "false negatives" or "false positives" in seedlist reports, where the results don't fully align with actual deliverability performance. This makes judging how accurate seed lists are for email deliverability a complex task.

The challenge is that while seedlists provide a snapshot, they don't capture the entire picture of sender reputation and inbox placement. They can indicate major issues, such as being placed on a blocklist (or blacklist), but they might not reflect subtle deliverability nuances influenced by sender history, content, or recipient engagement. This means relying solely on seedlist data can sometimes be misleading.

The reality of ISP filtering

Mailbox providers use complex, AI-driven algorithms to filter incoming mail. These systems analyze numerous factors beyond simple email content, including sender reputation, historical engagement, and even individual user preferences. Seedlists, even those with engagement imitation, cannot fully replicate this intricate, personalized filtering process. This is why a 100% inbox placement rate on a seedlist might not always translate to the same performance with your actual subscribers. For a deeper understanding of deliverability, see our guide on email deliverability issues.

Maximizing seedlist utility

Given these limitations, it's crucial to view seedlist data as directional rather than definitive. Instead of focusing on a single test's outcome, look for trends over time. Are your inbox rates generally improving or declining? Are there consistent issues with specific mailbox providers? Trends can reveal underlying problems or positive shifts in your sending practices that isolated data points might miss.

Supplementing seedlist data with other deliverability metrics is essential for a comprehensive view. Your email service provider (ESP) analytics, for instance, offer insights into open rates, click-through rates, and complaint rates from your actual subscribers. These real engagement metrics are often more indicative of your true sender reputation and deliverability performance than any seedlist can provide. Our free online email testing tool can help you understand these metrics better.

Leveraging Postmaster Tools from major providers like Google and

Microsoft (SNDS) is another critical step. These tools provide direct feedback from the mailbox providers themselves, including spam rates, domain reputation, and authentication errors. This data, combined with seedlist insights, offers a much more accurate and actionable picture of your deliverability health. To dive deeper, check out our Ultimate guide to Google Postmaster Tools V2. Regular monitoring of your bounces and feedback loop (FBL) reports is also essential, as these indicate problems directly impacting your deliverability and sender reputation.

Understanding what are the best tools and methods to measure email deliverability outside of campaign metrics will give you a fuller picture. While seedlists are useful for identifying immediate placement issues, they are only one piece of the puzzle. A holistic approach involves leveraging all available data sources to understand and improve your email deliverability effectively.

Data Source	Insights Provided	Limitations	Key platforms
Seedlist testing	Inbox, spam, or missing placement across various ISPs.	May not reflect real user engagement, susceptible to ISP seedlist detection.	Everest, GlockApps
ESP Analytics	Open rates, click-through rates, complaint rates, bounces from actual campaigns.	Only reflects what happens after an email is accepted by the recipient server.	Mailchimp, Salesforce Marketing Cloud, Braze
Postmaster Tools	Spam rates, domain/IP reputation, authentication status directly from mailbox providers.	Covers specific mailbox providers only, not a universal view.	Google Postmaster Tools, Microsoft SNDS

Building true deliverability

Ultimately, the most accurate measure of deliverability comes from your actual sending data and how your subscribers interact with your emails. Focus on building a healthy sender reputation by maintaining clean lists, sending relevant content, and encouraging positive engagement. High open rates, clicks, and low complaint rates are strong signals to mailbox providers that your emails are valued, leading to better inbox placement.

Ensuring proper email authentication is also paramount. SPF, DKIM, and DMARC records verify your sending legitimacy, helping mailbox providers trust your emails. Misconfigurations in these areas can severely impact deliverability, regardless of seedlist test results. A robust authentication setup is a fundamental pillar of good email hygiene. Read our simple guide to DMARC, SPF, and DKIM.

While seedlists provide valuable initial insights, they are just one tool in a comprehensive deliverability strategy. Combining their data with real-world engagement metrics, Postmaster Tools, and a strong focus on sender reputation and authentication will give you the most accurate and actionable understanding of your email program's performance. It’s about creating an overall environment where your emails are genuinely welcomed.

Example SPF recordDNS

v=spf1 include:_spf.example.com ~all

Views from the trenches

Best practices

Encourage replies to emails, even if routed to a ticketing system, to generate genuine engagement signals.

Establish a baseline of your email performance metrics, then monitor trends over time.

Always prioritize real sending data over seedlist results for the most accurate insights.

Common pitfalls

Relying solely on seedlist data as the absolute truth for inbox placement.

Ignoring real subscriber engagement metrics when evaluating deliverability.

Misinterpreting single data points from seedlist tests without considering trends.

Expert tips

Monitor trends in your data rather than isolated data points; a single blip can be misleading but trends over time reveal the actual picture.

Even if current metrics appear good, there is always room to refine your email communication for better accuracy and engagement.

Real sending data is often the most reliable indicator of deliverability performance, so use third-party tools as directional guides only.

Marketer view

Marketer from Email Geeks says that deliverability platforms' seedlists are mostly similar in terms of accuracy.

November 17, 2020 - Email Geeks

Marketer view

Marketer from Email Geeks says that consumer mailbox providers' filtering methods have evolved, making seedlists less insightful than they once were.

November 17, 2020 - Email Geeks

Summary

While seedlists from platforms like Everest and Glockapps can be valuable tools in your deliverability arsenal, their accuracy is not absolute. They provide a useful directional indicator and can help identify significant issues or trends, especially when used in conjunction with other deliverability tests.

The key is to understand their limitations, interpret their data within a broader context, and prioritize real engagement, sender reputation, and proper authentication. This comprehensive approach ensures that your emails consistently reach the inbox, where they can achieve their intended impact.