The Benefits of Having a Single Master List

Last updated at:


Streamlining your contacts into a single master list is a best practice to analyze your owned marketing strategy and optimize deliverability. In this article, you will learn how to funnel your contacts into a master list as well as when and why to use one.

What Is a Single Master List?

A single master list contains all, or the majority of, the profiles in your account that have consented to receive marketing content from your business. This kind of list is also often referred to as a master, main, or newsletter list.

When you create a Klaviyo form, you have the ability to customize a property around the source that is associated with these new profiles to reflect how they were added to your list. If you use a third-party form or lead capture to Klaviyo, you can likewise create a hidden field to pass this same source information. You will see this populate as $source property on your subscribers’ profiles in Klaviyo. In addition, when someone unsubscribes, we track how they unsubscribed.

Therefore, using the $source property, you can keep track of how profiles enter into your account even within your one master list by using the source property in segmentation. Note that the $source property will be overwritten by the latest opt-in.

Depending on the age of your ecommerce store, your master list might be years old. To make sure you’re not sending to inactive subscribers, periodically remove those who haven’t opened an email or made a purchase in six months or more. Check out our article on list cleaning for more information.

Why Use One?

There are several reasons why using a single master list is beneficial. Having a single master list will help you:

  • Maintain good data hygiene
  • Access list growth visibility
  • Optimize deliverability

Learn more about each in the sections below.

Maintain Good Data Hygiene

Maintaining good data hygiene means that you ensure your Klaviyo data is error-free and up-to-date. Having more than one master list in your account may lead to the same profiles existing in multiple lists. As a result, if you consistently email these lists, you may end up repeating messages and overwhelming subscribers with too much content. Note that if you send the same email to multiple lists and the same profile is in more than one list, they will not receive the same email twice.

Using one master list allows you to better track and organize who you send to. If you want to get more granular and targeted in your sending, then create segments from that list that are specific and can change over time based on the behaviors of your subscribers.

To learn more about creating segments, head to Getting Started with Segments. To better understand how segments differ from lists, read our article The Difference Between Segments and Lists.

Access List Growth Visibility

For every list in Klaviyo, you can access a growth report to capture data around your list's growth over time. Having a single master list allows you to see these changes on a larger scale, gaining insight into how your subscribers behave overall rather than only seeing growth for small portions of this audience.

To find this report, click into your main list and navigate to Reports > Growth Report.


As mentioned above, you can use $source as a hidden field in a form to track how a profile enters your main list for further analysis. Check out the example in our Guide to Properties for more details.

Optimize Deliverability

Cleaning your lists is key to good deliverability. Having one master list makes list cleaning easier as it is streamlined in one place and allows you to remove outdated, unengaged profiles more efficiently.

In addition, to maintain good email deliverability, target engaged profiles in your account with email content and continually monitor your deliverability performance. To do so, you will create an engaged segment based on your master list. Since you plan to email these profiles, you want to make sure that they have subscribed to email marketing, so you will include that they are a part of your master list, as shown in the engaged segment below.


If you have multiple master lists, this makes segmenting more difficult since they could belong to any of those lists. You may miss engaged subscribers if you were to leave the list that they belong to out of your conditions.

Moreover, by adding the condition that someone is a part of your master list in segmentation, you make sure that you only email those who have consented to email marketing. For more information on handling consent, head to our articles on Consent in Profiles as well as Uploading and Segmenting with Consent.


There are two main exceptions to having one single master list:

  • A list for profiles acquired via giveaways
  • A list dedicated to in-store customers

In either case, these profiles can be placed in separate lists from your master list since you will want to easily differentiate these customers from the rest of your ecommerce subscribers.

In-Store Signups

If you have a brick-and-mortar presence, you may wish to keep those profiles separate from your ecommerce store. They may have consented to different channels, in which case you do not want to confuse their consent status with that of your ecommerce subscribers.

In addition, you may have different offerings in-store from your online catalog, and will, therefore, send each group different content. In either case, having a master list for your ecommerce brand and your brick-and-mortar store may be right for you.

To learn about how to gain in-store signups using QR codes, head to our Guide to Using QR Codes to Gather Subscribers.

Giveaways or Event Promotions

If you run an expansive giveaway and do not want people who sign up for this promotion to be included as a subscriber in your master list, create a separate list for this temporary interest group. However, if you plan to communicate regularly with this group, then you may want to include them in your master list to receive marketing content from your brand.

Moreover, if you advertise multiple events via forms on your site, you may want those forms to lead to their own lists in Klaviyo to keep track of each individual sign-up. Though $source (as discussed above) keeps track of when someone submits a Klaviyo form, if you have multiple forms leading to the same list, the source will be overwritten by the latest opt-in. For that reason, having a designated list for each lead capture is the best practice to keep track of sign-ups. You can then create segments with the condition that someone has opted-in to a specific list.

Additional Resources

Was this article helpful?
1 out of 2 found this helpful