Seed Based Email Tests: Best Practices

Estimated reading time: 5 minutes

A seed based email test involves sending a message to a list of test email addresses set up with different inbox providers. Such a list is called a seed email list. At GlockApps, the seed list contains 100+ email addresses utilized specifically for Inbox Insight tests. 

However, sending a message to 100+ email addresses at a time may be unsafe for your sender reputation especially if you have a new domain or a domain without a sending history behind it.

In this article, we share the recommendations on how to safely run Inbox Insight tests without hurting your domain reputation and deliverability of your email campaigns.

Consider the following best practices to get as relevant email placement results as possible and avoid a negative impact on your reputation:

1. Test Real Message in Real Environment.

An Inbox Insight test will produce relevant results when you send the message to the seed list exactly the same way you are sending your email campaigns to your real clients. It’s not recommended that you test a message with one test id string in the body and/or an email without a Subject line. Although the email content is not the major factor, it can still make a difference for where the message is placed. 

Therefore, consider these best practices in order to get the most relevant results possible:

• send a message with a real email content and Subject line to the seed list;
• send a message to the seed list from the real email address;
• send a message to the seed list using your email account or email service provider that you use to send email campaigns to your real subscribers.

2. Import Seed List in Contact Group.

We encourage you to avoid putting all of the seed email addresses in the To:, CC: or BCC: field when running a test. This increases the likelihood of the email to be bulk mail and may result in a higher Spam placement ratio.

Instead, consider this method:

• download the given seed list as a CSV file with the delimiter supported by your email service provider (ESP);
• create a new group (list, audience etc.) in your ESP;
• import the seed list into a new group (list, audience etc.);
• send the message with the test id code to the imported seed list.

This way, ESPs typically create an individual message for each recipient in the group, which eliminates the likelihood of a bulk email sending and reduces a spam score.

3. Use Split Seed List.

In the scenario when your ESP doesn’t support the creation of a contact group or list and you have no other choice than sending a message using the seed email addresses in the To: field, we recommend using a split seed list for an Inbox Insight test. 

This helps reduce the email’s spam score with SpamAssassin, which adds 0.20 points to the spam score when more than 25 recipients are used in the To: field at a time.

When a split seed list is chosen, GlockApps returns several seed lists with 25 email addresses on each. Sending a message to no more than 25 recipients at a time is considered a safer mode. 

Here are the steps:

• choose to show a divided seed list in GlockApps;
• download the returned seed lists as CSV files;
• copy the seed email addresses in one file and paste them in the message’s To: field;
• copy-paste the test id in the message body or Subject line and send the message;
• repeat the process for each seed list.

Important! Ensure to use the same test id string in the message sent to each seed list. This makes the email placement results to be written to the same report.

4. Customize Your Seed List.

You can customize the seed list for the test by excluding the inbox providers, which don’t appear on your real email list. This will provide you with a shorter seed list and will allow you to focus on the message optimization for the most important inbox providers. To customize your seed list:

• start a manual Inbox Insight test;
• remove the check marks near the providers you don’t want to test with. You can exclude individual providers like att.net, mailo.com, gmx.net etc. or large groups like Asia/Pacific or Russia;
• click “Next” to go to the next step.

By excluding irrelevant inbox providers in the sending account settings, you can customize the seed list for proxy tests. In the automatic test settings, you can customize the seed list for the given message.

5. Set Delay between Messages.

To avoid email reputation issues, a good practice is to set a delay between the messages sent to the seed list. Although this makes the test working slower, you will be on the safe side when it comes to safeguarding your email reputation. You can set a delay between the messages:

• in your ESP if such an option is supported;
• in the sending account settings in GlockApps – the delay will be applied to the messages tested via a proxy email address;
• in the automatic test settings in GlockApps – the delay will be applied to the messages sent by an automatic test.

6. Make Intervals between Tests.

Sometimes, you may need to test the same message more than one time after making changes to its content. In this scenario, it’s recommended that you make reasonable intervals between the tests – 15-20 minutes are acceptable. Running multiple tests for the same email within 5 minutes or so is not a good practice – you may see your results getting worse from test to test.

Closing Thoughts

The Inbox Insight tests are a powerful instrument to measure the effectiveness of your email communications on pre-send. By testing your emails, you can identify the content elements and infrastructure issues negatively impacting your deliverability. 

The best practices provided in this article will help you run email tests in a safe mode without hurting your domain reputation and receive as accurate and relevant email placement results as possible.