Seed Lists: What Are They for and How to Use One?

What Is a Seed List?
Valeriia Dziubenko Valeriia Dziubenko 15 december 2022, 10:00 198
For beginners

Email marketing can generate a high return on investment, but there are many things you need to know to use it effectively. One of them is a seed list, which refers to a list of test email addresses that you use to monitor what happens in the inbox after sending a campaign. 

The seed list gives you a good overview of your deliverability rate. It's essential to test your marketing campaign before deploying it en masse, which is why seed lists are so important. 

Reasons to Create a Seed List

1. Assess Deliverability

Deliverability refers to the percentage of your emails that get to the intended recipients’ inboxes. Many things affect this metric, such as your email service provider (ESP), type of IP address (shared or dedicated), and sender reputation

The value of 95% or higher represents a good delivery rate, although the average hovers at around 80%. A seed list lets you test your deliverability rate on a small audience to give you a clue of what it’ll be at a large scale. For example, if you have 30 email addresses on your list and your test message gets to 27 of them, that represents a 90% deliverability rate. It’s likely that you’ll see a similar rate when you send messages to over a thousand subscribers. If the deliverability rate for your list is low, it’s a signal to make changes before sending the campaign en masse.

2. Preview Your Campaigns

It’s important to get an accurate look at how your messages will appear in recipients’ mailboxes before sending them to your subscribers. When you send messages to your seed list, you can see how it appears in the recipients’ inboxes on different email clients. If you notice any issues, you can correct them at this point to avoid embarrassment.

The seed list gives you an opportunity to preview your campaign early and spot any serious flaws. For example, if you notice that your email isn’t optimized for mobile viewing, it’ll be wise to optimize it because many people read emails on their smartphones.

How to Create a Seed List

  • Include addresses of people that are willing to provide feedback. Apart from your colleagues, it might be appropriate to include friends, family, or people that have a cordial relationship with you and are willing to take the time to give honest feedback. Avoid adding subscribers that haven’t engaged with your content for a long time.  The most appropriate way is to create a number of dedicated mailboxes on different services and platforms.
  • Add addresses for different email clients and devices. This will help you get a broader view of how your messages will appear on different platforms. For instance, if your list is skewed to one email client, e.g., Gmail, you may overlook problems on Yahoo Mail or Fastmail. 
  • If you want to test an AMP email, ensure that the addresses on your list are using one of these clients: Yahoo Mail, Gmail, or FairEmail. These are the few clients that currently support AMP emails, so you’ll need them to get an accurate preview. If you can’t find a good variety of addresses for these clients, you can create accounts by yourself and use them for testing. 

Once you've gotten a good list, ask the people on it to interact with your messages and report back any issues they encounter. 

How to Run a Seed List Test

Seed list testing ensures that you can spot mistakes and correct them early on before sending your campaigns to a large number of recipients. With the list ready, the first thing to do is send the test message. If applicable, you may send it more than once using different ESPs to see if there are any differences. Then, follow these steps to evaluate your test (or use it as a checklist for a trusted person):

  • Verify that the emails were successfully delivered to the inboxes and note the deliverability rate. 
  • Ensure that the recipient's name, subject line and the preview text are displayed correctly. 
  • Open the messages to check if they display as expected. Check the image and text alignment and make sure that the message is viewable with different screen sizes and resolutions. 
  • Click the links in your message and check if they redirect you to the intended web pages.
  • View the messages using different email clients, devices and web browsers.

The checklist covers the most important things to look for in your emails. If everything’s ok, then your campaign is likely good to go.


There are many things to consider if you want to run effective email marketing campaigns, and seed list testing is one of them. It’s essential to test your campaigns rigorously before sending them to get better results and avoid upsetting your customers. You should also endeavor to pick a good email service provider, e.g., UniOne, that’ll make it easy for you to send campaigns and monitor their performance.

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